The only problem I see with this method is that the finished cradle will be the same size as the boat and when you put the carpet in, it will be smaller. I found it easier to measure the hull with hanger and then cut 2 boards the aproximate shape of the hull and put tyvek (fedEX envelope) over it and fiberglass an inverse mould then sand to 600 grit and paint with mould release and form a cradle. That way the finished cradle is about 1/4" larger than the boat and the carpet fits perfectly.