RE: grip and arrow flight
Two things that effect tuning nightmares is inconsistant grip and follow thru. You can technically hold the bow any way you want as long as you do it the same way EVERY time. So the less contact you have the more repeatable it is. A lot of people that have trouble paper tuning a bow usually have form problems, not tuning problems. Which is also why someone else can't tune your bow for you.
Paul