Something else that has worked for my chest is to do heavy dumbbell flyes. It's opened things up nicely and I have also been doing a pyramid of sets on flat bench. I started with 135 for 14 reps, 155 for 12, 175 for 10, 195 for 8, 215 for 6, 235 for 4 then start back the other way and it's been a killer, but it's worked. My chest if fuller now than it's ever been