Yeah i don't know what the proper mechanics are, every person is built a different way and you have to feel whats comfortable to for yourself. I know when i use to pitch i would experiment with different arm angles some would give me more velocity,control, and deception but i would end up going with what didn't make my arm as sore the next day. I was also aloud to throw until i said i was tired. This is something the Jays have to trust there players with and the players have to be smart about keeping there arms healthy, it's there careers after all.