Im really tired of people saying they cant isolate. Try doing flies before your presses..but contract and squeeze your chest very forcefully at the top of the movement..this will indeed stress your inner chest harder and preexhaust it for your presses. Your chest is made up of 2 major fan regions. And yes, you can overstress the top fan with incline presses. Overstressibng in comparison to the lower section is basically isolating your upper chest to a degree. If you truly cant isolate anything to no degree..then dont waste your time doing incline benches..just do flat's and you can grow your own set of man boobs.