I don't have all of the instructional movies and or books, but I have reviewed several. When I started shooting traditional again several years ago after many years of not shooting, I talked with several archers and read several books in search of the perfect form. I tried to copy several "famous archers" and several local folks who are quite good. I became very frustrated and through alot of trial and error have developed a style of my own, nothing new more like little bits and pieces from many others.
This year I was fortunate enough to go on my first elk hunt (I live in the east) I did not harvest an elk but had an incredible exprience, another story. I did however spend alot of time practicing longer shots than I was accustomed to taking, 30-40yards and on occasion 45yards. I became pretty confident after flinging many many arrows. The practice did pay off more during a New York hunt as I did take a whitetail at aproximately 33 yards, a shot I wouldn't have even thought about the year before. I would have to say the form/ system which helped me the most accomplish my longer shot accuracy/confidence was Byron Fergusons' book becoming the arrow.
I guess the bottom line for me is that as long as I remain open minded and take the time to practice my prefered style may continue to evolve. However I save the experimenting for the off-season, practice enough to be confident with whatever system you choose, and most of all know your own limits.
Who said you can't shoot a longbow 3 fingers under!! Umm Umm Umm those venison steaks are very tasty!!

Good Luck

Jim