I'm not sure I'm the best person to give advice on how to use Shadows as I've lost my last 4 games with them...but there are a few lessons I've learned the hard way about changes in Armageddon and maybe you might learn from my mistakes.
Hash's Guide to Shadow Dancing:
Shadows are frail, even with the uplift from SFoS stats to the new Armageddon stats (and if you're playing with tourney stats it's actually a downgrade to Armageddon...yeah I know the ship is harder, but the WAR choice is worse than the old tourney WAR choice), you're still not a "stand there and fight" sort of ship..don't get me wrong, a hard hull will make you last a few turn but your opponent will outnumber you and wear you down with multiple weapons. Bottom line is that the way ancients take damage means that 100+ hits is not going to last very long, you'll be adding up the hits faster than Reaverman's post count
Still there are a number of strategies that can make Shadows devastating...and they do change significantly in Armageddon due to the changes to fighters and stealth mainly but also due to the loss of the Turret arc on the Shadow War level choice (and Armageddon choice for that matter). Here are my top SEVEN (I could not think of ten

) tips (some are more relevant to campaign play rather than one-offs)...
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Shadow rule number 1 - If they can't get you in arc, they can't shoot you.
You may be frail but you sure can dance! You can outmanoeuvre everything apart from fighters so you should take advantage of that by always trying to place yourself out of your enemies worst firing arcs (or better yet out of arc completely). EVEN if this means you don't get a shot yourself...you take damage horribly, especially from DD, and TD weapons and unless you're SURE you'll take out whatever has just CAF'ed you in the first shot - wait until you get the best opportunities to fire...
Shadow rule number 2 - Patience is more important than aggression.
If you've played Shadows before you know how satisfying it is to go out and blow up something nasty the opponent has in the first two turns...and then you get upset when he kills your big ship in turn 5 or 6 from multiple fire from his small support ships. You lack patience! You don't NEED four or five turns to kill something...often you just need a single shot. If you're playing with a turn limit - see how much time you can spend keeping out of range while you're opponent scramble to keep up with you (doesn't work well with Whitestars!)
If your opponent has multiple small ships this is even better - stay well out of range for most of the game (if you can, asteroids are great for this) and about turn 8 or 9 zoom out and try to pick off a couple of stragglers. Chances are you'll take out a ship or two with minimal damage to your monstrosity and claim a great victory for the forces of chaos! Your opponent may look dimly on your sportsmanship however...
Shadow rule number 3 - Fighters have teeth. BIG TEETH.
Shadows were always a little vulnerable to repeated fighter attacks, mainly because they were the only vessels that could regularly outmanoeuvre them as they moved last. Before Armageddon though I pretty much used to ignore fighters, I hardly used my own fighters since you had to buy them as independent wings and the Shadow Ship (and Hunter in tourney stats) had Hull 6. If the Shadow Ship was really irritated by fighters, it's T arc let it get a shot off if you really wanted. The Shadow Scout of course had it's stealth to divert 2/3 of all fighter attacks...
That all changed with Armageddon - fighters are back with teeth. Armageddon introduced several changes that impacted on fighter survivability. Fighters now fire first and one of the new fighters (the White Star fighter) is capable of DD and has multiple attack dice. To top it all off, fighters no ignore Stealth with 1"...you can kiss goodbye to your scouts when playing against ISA! Because the WS fighter is fast - rule 1 and 2 become difficult to apply and it does obscene amount of damage - roughly 5 will kill a Scout in a single turn - before the scout itself has an opportunity to fire!
Against the Hunter and the Ship the fighters are still nasty, mainly because once they get on you, they are almost impossible to shake off...you can use your own fighters now against them but their dogfight score and numbers will probably buy you a turn before they come back to nip at your heels. Your lack of a turret arc on the WAR choice means you can't even take the desperate attempt to shoot at them with the molecular slice (as they will be out of arc) So how do you cope? With difficulty...you're going to take a hit, you've just got to plan it so its the last time you're opponent gets to use those fighters. Now the scout has a nifty AF weapon but as fighters move last, its rare that an enemy will remain in your arc...that's why you have to force the issue.
Step 1. Keep the Scout well out of range of the nasty stealth ignoring fighters...keep you own fighters with 10" range of your main ships.
Step 2. Bubba (your opponent) moves his fighters to attack your other ships...feel the pain.
Step 3. Next turn you move your scout (18" move is good for charging) to target the opponents fighters with your AF gun.
Step 4. When it comes to move fighters - YOU move your fighters first and engage the enemy in dogfights...tie up as many enemy flights as possible, don't worry about massive penalty to dogfights YOU want to lose (or rather don't mind)
Step 5. Bubba most likely wins the dogfight but can't move his fighters...now the ships can fire!
Step 6. Your scouts AF weapons wipes out the scum - all it cost you was a few of your own fighters.
Other methods exist of course, including making sure you cover each ship with a scout (including the scout providing cover if you can!)...if the scout survives the initial fighter assault, it should be able to clear up the mess.
The last anti-fighter tactic is desperate but it involves getting up close to an any vessel about to explode and unloading on them...the resultant explosion MIGHT take out a few...if it doesn't damage your own ship too badly.
Shadow rule number 4 - When the going get's tough, RUN!
Pretty obvious really but shadows regenerate - most other ships do not. With that mind, if the battle starts not to go your way - MOVE out, try and hide behind something and maybe your regenerate will bring you back into the battle later on. If playing a campaign game then consider leaving the field...
Shadow rule number 5 - Winning the battle is not as important as winning the war.
This rule is applicable to campaigns but consider what you want to achieve from each battle. Most of your choices cost you double RR to replace that a standard race PL ship, e.g. a Raid ship costs EA 15RR, it costs you 30RR!
Let us say you need to defend a Strategic Point in the campaign and you can field a Hunter and a couple of scouts...now you're opponent has a lot of fighters and other Capital ships, while you *may* be able to defend the point, you're unlikely to do so without incurring losses. It costs you a massive 30RR to replace a scout...and 15RR if you lose a strategic point, you do the maths! However, you're opponent gains 10RR for taking a new SP, if you manage to take out a Skirmish ship he's broken even...if you manage to take out more and leave without losing a ships...well he's made a loss!
In this situation, say you don't lose any ships but lose the battle (and strategic point) - then you lose 15RR.
If your opponent loses a Skirmish Ship (RR) and a Wing of Fighters (5RR) - he hasn't gained any RR...so if you add another Raid Ship on to the heap , he's also lost 15RR...it's at that point you've broken even (you and he have lost the same value of RR from your fleets). So if you can kill (or cripple/damage) any more after that...well that's a bonus and means he's lost more RR than you, even though he won the battle...remember KEEPING your ships alive is MUCH more important than winning one battle in the long term, no matter how large.
Shadow rule number 6 - Know when to fight, and where to fight.
Another campaign one. This is fairly simple too but your key assets are your SM and initiative...the later means that means you can often chose the battle location, the former means that hazards to others are a lifeline to you!
What am I talking about? Terrain my friend, TERRAIN! Terrain gives you cover, something you need with shorter range weaponry, and also something to dance around - watching your opponent try to keep up with you in an asteroid field (or Shadow regeneration zone as I like to call 'em) is most amusing I assure you.
Also - this may also sound very simple, don't fight battle that go against you if you can - if you're 3 FAP down against your opponent on open terrain then don't fight! Turn up to claim the XP ad simply leave (or if annihilation simply don't turn up). You're most important asset are your ships, not the strategic points. What you really want to turn up is an Ambush scenario...a free turn right in front of your opponent can be utterly devastating to the opponents fleet taking only minimal risk for yourself.
Shadow rule number 7 - Two Hunters is usually better than one Shadow Ship.
There isn't a huge difference between the Hunter and the Ship anymore, I used to prefer the Ship because its turreted weapon allowed the Shadow to exploit the SM ability to a greater extent but sadly, Armageddon has taken that away from me...
The Hunter is now by far and away the better choice over the Ship, 12 AD SAP BEAM TD beats 8 attack dice and the ability to target 2 (or maybe 4 if you can split the beam on both Hunters)...still the model is god awful and not a "proper" Shadow anyway so its up to you
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Well that's it so far, basically you need to put the survivability of your ships as the top priority, recognising that you have the time to make the telling blow, your opponent often does not. Armageddon makes your life harder as it strips your scout of its greatest protection and makes fighters, which were good against Shadows before, considerably more lethal.
To paraphrase the greatest heavyweight of all time..."Dance like a Shadow and err sting like one too"
