I always figured cloth is stronger. I assume you're talking about chop strand mat. I just built race hatches for my 28 Cig using two layers of 6oz. bi axial cloth on top and one layer on the underside. I used epoxy resin and I can jump up and down on them with only a little flex. And I used 1/4 inch birch plywood. Very light and strong. I'll post some pics when I shake this hangover.