PH4 - you're maxed out at 35 spaces right? For me, I use 4 Brutes and 19 buccaneers. Just don't clump them all together.
Not for farming, if I actually want to get 3 stars then I go 4 brutes, 8 gunners, 8 buccs, and 3 bombers
Brutes can take a beating, but watch out when they hit mortars; as soon as they attack a mortar it changes its target.
Happy hunting. Remember, there's always more than one way to attack, just keep doing what works for you