Dtrain....Cut a few lawns, or shovel some snow (Talk about good core workouts) but buy Stevens "Tuff Cuff". You will not have to worry about asking more and more questions. Just follow what it lays out for you and work hard.
I have read it and gave it to my sons varsity coach. He has immediately started to use it. I'm not trying to do anything but give you a hand here...Steven isn't giving me anything for recommending his book, he doesn't have to. I'm all about helping guys like you who "REALLY" want to become better pitchers and it is obvious from all of your posts that it is your desire to get better. Well spend a few bucks and get your nappy little tail to work!
I myself enjoy our forum but the problems that come with a guy like you looking and looking is that you spend more time looking and get a wide variety of answers which can be confusing and can get you side-tracked. This is why I have told you to get a plan and stick to it. Stevens book will start you down that path...so Hop to it! Get moving!