Pamela, I haven't kept up on what you are making but the deck area behind the coaming gets as much or more stress than the hull in normal use. Whether 4 or 6 oz is needed for strength is a function of the design and materials. I wouldn't bother with 2oz, can't say with regards to strip boats but my experience is with s&g. Have you looked at Nicks book with the description of the glassing for various uses, light, med, heavy? It's a good guide for any kind of wood/epoxy/glass construction. For most uses 4oz on the deck is sufficient.