i shoot 28.5 /2117/3 sets of 2 2inches vanes / not able to obtain screw insert weights/i put a weight between the arrow and target point / this gives me a 14% foc /will having the weight where it is have same effect as weights behind the insert

I suppose you are talking about the little brass washer weights that you can put behind the point/broadhead? Yes they will improve the FOC the same as a heavier broadhead or weighted insert. You are limited as to what you can add though.

Dan