Let's see....a combined fleet group would be:
Escort Group - 8 x Gazelle-class EC, 2 x Chrysanthemum-class DDE, 2 x Fer-De-Lance-class DDE
Group 1 - 8 x Gazelle-class EC
Thrust - 6 - all ships thrust-6
Hull - 301 (Behaves as Squadron) - (8 x 176 + 4 x 400 =3008)
Traits - None
Crew Rating - 2
Defence - 4 - uses lowest
Salvo Defence - 112 - combined directly
Screen Defence - 0
Armour - 6% - averaged (2x0+2x1+8x3 gives an average armour/2)
Turrets - Bonus +4 - 8 Damage (Medium Range)
Barbettes - Bonus +4 - 35 Damage (Medium Range, Radiation) - 30 Damage (Very Long Range, Radiation)
Missiles - 36 Missiles
The group's base defence against a missile salvo is 48 (12 x 4) plus its 112 salvo defence means cracking it with missiles would take some doing.
Double-punch with advanced missiles allows you to put 144 missiles on target, but the base defence means only 24 from each salvo (total 48) will get to point defence range through ECM and evasion. Even if the 'slower' missiles are multiwarhead missiles (not unreasonable given how lightly armoured Imperial DDEs are), there's enough salvo defence to compensate on the multiwarheads by applying 30 salvo defence and still being able to stop the advanced rounds as well.
Annoyingly, the High Guard flight times lists flight times for thrust 6 (ortillery), 10 (most weapons), 15 (long range/advanced) and 12 -but there's no thrust 12 missile or torpedo that I can see. Which is a shame as it'd let you potentially concentrate a third volley in a time-on-target attack.
Bay Weapons: All bays suffer DM-2 when attacking targets of less than 2,000 tons.
Given that the Capital Ship combat relists most of the penalties and is a fundamentally different system, I'm not sure if that penalty applies or not - as noted, there's already a 'shooting at small targets' penalty for non-turret/barbette weapons