Phil, There are many on these forums that SEEM to think that "hunting form" is somehow different than "Target form." Terry Green says it as well as anyone, "form is from the waist up..." That is, once you learn good form, it WILL NOT matter if you are on your knees, in a tree stand or hanging by your toes. You can achieve good form no matter your "underpinnings."
Rod will teach you to achieve good back tension and shooting technique which will allow you to shoot from many odd positions well. AND, by the way, he IS a very successful bowhunter too.