RE: How much should we teach?
It sounds as if you've done well in providing the direction he needs. My Dad hunted with me about as many times as I can count on one hand. I really would have liked to have him with me everytime I went to the woods, and still wish that even today. Learning as you go takes a great deal of time, often to find you've sought information from sources once thought accurate.
As a father, I would go with him as long as you are able. Only shadow him if he needs room, but always be available. He'll appreciate it as he grows older and you'll still be able to tutor, all the while sharing inhisoutdoor success. My son just turned 13, took his first last seasonand I'll go as long as I'm able. No matter how good he becomes, you'll still be able to contribute... it's a Dad thing.