When I heard this rule, I thought you would get to pick and choose when to invoke Redundancy. While this would (in my opinion) be a cool interpretation and a big damper on the grievous functional crits (the 1-6, 2-6, 3-6, 4-4, 4-6, maybe the 4-5 and 6-3), if other folks think this is too time-consuming, I can work with that.
If you're forced to use Redundancy immediately, I suggest the following:
A). Raid:1, Battle:2, War:3, Armageddon: 5. This'll probably fool us and be less crit armour than we'd think. I can be convinced -- pretty easily -- that this needs to be customized per ship because of Hull value effects, especially at Raid. For example, it wouldn't be hard to argue that the Poseidon and Drakh Mothership should be Redundant 5 and T'Loth, Bimith, Solarhawk, and Drakh Fast Destroyer Redundant 2! Maybe make the Haven even worth a crap, give it Redundant 1??
B). Still nothing on Civilians. They're civilian, not even a ship with a priority!
C). Still nothing on Vorlons or Shadows. They don't take criticals, just additional damage per the Ancients table mechanic. I hate this, but I'm only considering it on the basis of fluff, which, I know, is stupid. But they don't have systems as much as ... organisms. And, you need precise to get there anyways, so why not give Precise its due here? Maybe we need to give them something different. Mentally shrugging my shoulders and saying "I dunno."
D). Still nothing on Bases. They're already freakin' huge. Also, same "you need a 7" as above.
D). Redundancy repairs for free between scenarios on any uncrippled ship. No bookkeeping necessary.
E). Redundancy fails when the ship is crippled; it's a Special Trait that falls off like Interceptors.