[strick]

On the stringers I would grind out questionable areas with the grinder and then re glass to beef en it up. Myself I don't think there is anything wrong with using plywood as long as you do it right. I've used both epoxy and vinyl ester over foam coring material without any problems. Don't worry about debonding your plan sounds OK but you will need to thru bolt the transom core with something on either side of the transom say 2x4's to suck the new transom coring to the outer skin. If you use plenty of resin you should have no debonding issues. One thing to keep in mind is that some of your transom coring materials are so dense that they are nearly as heavy as plywood so the weight difference would be negligible. I would do all your repairs in epoxy and for making parts use your vinylesters and polyesters. I used vinylester on the majority of my 20 restore because it was a little cheaper then epoxy and I wanted to see what working with it was like. The fumes are a real PIA but otherwise I'm happy with with it and it appears to be plenty strong.

strick