Whats been successful for you in bringing out your upper chest? I changed things up about a couple months ago and have finally started to see some real progress in my upper chest, still not filled out but compared to the 1.5 years before that, its been a huge change.
I finally found out how to hit my upper chest and actually feel it, through people on here, youtube, other online sites etc. normal exercises just didn't cut it for me. Different pec insertion? Or whatever I read.
Anyways for incline bench, I don't go for my max weight, I go somewhere where I use my shoulders minimally and lift with my chest mainly. And I really bring the dumbbells down and a bit forward to where your nips are haha (really got to find the angle and such that works for you by playing around with it). Also for many exercises such as standing shoulder press, front dumbbell raises, dips, bringing your chin down to your chest and really squeezing down has helped a ton, at least in my mind it helps a ton as I can finally feel it by doing that.
This is all based on my problem that I wouldn't feel it, not sure what the case is for you, but thought I'd throw it out there incase it was.