We think it will work out well Stewart. We will pull off a test panel with 200gsm/4mm spruce/200gsm cloth once we have the stations set up to get some numbers. Considering that ply usually have three layers of epoxy on each side plus paint we should be good if we are careful with gaps (epoxy is heavy and expensive). I have also been talking with strip kayak and canoe designers about how to build light and got lots of tips. We have discused weight at length but only the test panel will tell. We will also do some experimental stuff inside the hulls to bring weight down as far as we dare. It will all be documented in the blog. Phill have come up with some new (to me) ideas which it will be fun to implement.