Of all toons in that squad the health/protection/defense balance with GK has the most flexibility. If you have 6e mods on GK it kinda doesn't matter beyond that as long as you're not doing silly things like putting on a 2x mod set. I think 1 defense with 2 health sets is good, and health/defense/or protection primaries are pretty good. I would consider though that if you are gonna go 1 of those primaries it might be smart to go all 3 primaries the same. I know defense has diminishing returns but getting GK a high a possible on defense is not 1 of the cases where you would regret it.