Swingbuster, we want the bat in a 45 degree angle past the hitter's ear. We've had success with that. However, we won't change a hitter until they prove to us that they need changing. We use the top shoulders and hands as a unit. They rotate slightly all together. I can't stress enough slight rotation. Some people try to do this and move a couple of inches. That destroys the whole thing. We do teach hands and I know several here do not. However, we teach hands only when it becomes apparent that they are trying to swing around the ball and not to the ball. To set the hands where we want them, often all we really have to do is the rolled up towel under the lead arm's armpit. As per the back shoulder, I think someone alluded to that in this thread. We don't coach that other than to say relaxed and comfortable.
Oh, the bat at a 45 degree - here is how we arrived at that. Say you were in an alley with a bat and a bad man came along to attack you. How would you hold that bat if you had to fight for your life. I'm betting you would load it in a 45 degree angle. We simply are letting our hitters do what their instincts tell them to do. JMHO!