So after seeing the stringers on my blog for the past few months (sorry), you can now see that I have them in place. I had to pull the transom off the boat, and was then able to slide then into postition. They curved nicely and fit right into the curve of the hull. I then glued them in using fillets and set about glassing over them. Once covered with two layers of glass cloth, they seem to be quite rigid and have stiffened up the hull panels considerably.