2- 3 % would be fair <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />

just putting weight difference into schrs formula wouldn't be fair ,

true weight difference doesn't transfer to weight in boat as crew weight is dynamic and not as big a penalty as a fixed weight

In ideal world if fattys could get this sorta allowance I would put into extra power to drive my bulk rather than look for handicap advantage , who wants to win that way .