Nothing wrong w/ modifying your form--If you are not modifiying your form somewhat for diff. bows, then you are ignoring the particular nature of a given bow and your particualar physical strengths and weaknesses. I have 3 distinct forms of shooting, to adjust to particualr situations and the characteristics of the bow I happen to be shooting at the time. When I shoot heavy bows, Iam bent over and shooting with the limbs horizontal- which has very little in common w/ the upright posture and slightly canted bow form that I use w/ligther weights-- its just a matter of adapting("modifiying) to circumstances. Shoot what you like, how you like. There are no rules here. Just enjoy, learn, adapt--its all part of the traditional spirit.