Oye. I was reading through this thread getting more and more disappointed until I read Scotty's post. Trying all kinds of rhythm variations (i.e. drop sets, super sets, so on) seems silly to me. I don't think you were referring to cardio for your pecs, were you? Would there be a point in benching, say, 100 pounds 30 times when your max is 300? Then why would you do it after a work set? Which brings up another thing. A set is either a work set, or a warmup set. There's no other reason to perform a set. Pre-exhaust and drop sets only limit your ability to overload your muscles. When I was flat DB pressing 65x10, I decided to try pec flye pre-exhausts. After a month of pre-exhausting I went back to doing it the traditional way, and had a hard time lifting 55x6. Waste of time.
Take a couple weeks off from lifting for your chest. Work your rotator cuff in the meantime. When you go back to it focus on form and on the mind-muscle connection, rather than fancy techniques.
</end rant>