I firmly believe you will get the best chest development from DB bench but a combo of DB and BB work will give size and strength. You can't work at anything with stalling, especially with chest.
As far as DB work this is what I have learned to do when performing the exercise and things like skullcrushers. I kick the weight up and fall back and while doing so extend my arms so that by the time I'm on my back the weight is extended with arms locked.
I agree with you that a combo of BB and DB is the best for mass and strength, but most importantly for variation's sake. Even if you're a PLer gunning for a big bench, periodize with DBs to mix things up and also to help with the overall strength (i.e. stick with sets of 3-5 with very heavy weight). I'm finally back to BB benching after doing 6 weeks of nothing but DB benches and my right shoulder is starting to get back to normal (which tells me that it fortunately was not a rotator tear issue).
When I do DB benches, I grab the bad boys from a standing position, then sit and rest them on my knees. Slight up-kick to get them back as I lie down flat. I don't extend them straight up with arms locked. I bring them back to the starting position, so that the first rep is basically the hardest one because I'm pushing all the way up. I also try always to bring them down far enough so that the DB handle is either even with my chest level or slightly below it.