Minor update, I've run a few practice games with a lot of variations on these ideas discussed here, and the actual favorite Double Defender list I finally came up with is:
Rexler Brath 37, HLC 7, Ion Pulse Missile 3, Shield Upgrade 4, Veteran Instincts 1 = 52
Colonel Vessery 35, HLC 7, Shield Upgrade 4, Decoy 2 = 48
It's less overall firepower than Brath with Predator, Lone Wolf, or PTL, but it lets you do some useful things.
-You have a good counter to Phantoms (PS10 HLC!).
-You can Target Lock PS9 guys on the first pass, at long range, so you're suffering less from not Focusing for defense.
-You can make large ships nervous near board edges and the asteroid field.
-You can switch up firing order when useful, either HLC can be PS10.
-PS9 arc dodgers have to stay a little honest. They know where 1 Defender will be, but not the other.
Just thought I'd share in case anyone is still interested.