exactly the same with me, my shoulders and tri's take all the work if I do it with a BB. And my poundage is considerably less, when I did it with a BB before I think I got up to 99lbs for like 12 reps, and on flat bench I can rep 193 for 3 reps without going to failure. For dumbells on incline I manage to use more chest, but still I can only get 60s for 8 or 9 reps. Still the incline will be a good change and shoulder strength is important for a big bench so i for your goals I think its a good idea