Like you, I have been considering shorting a 70" white oak flat bow. Iam also thinking 1" off both limbs. I do not know this, but Iam thinking that a bow that has weaker outer limbs,ie. the last 10" is more likely to be enhanced by shorting. If your ends are somewhat "Whippy", than shortening should bring about the desired effect. That said, I have shortened several glass bows, and all I got was a bow which pulled a few more pounds, but with no noticeable enhanced performance,-- actually lost some performance on one of them--really regret what I did to that bow. But, what the Hay? Its a wooden bow, the worst that can happen is you have the pleasure of making another one. this is how we learn, is it not?