My entire seat is rotted out and the upholstery is dry and cracking. Anyone know a good source for the upholstery? I have some marine plywood and the foam is fine. I just want a pre-formed upholstery piece to staple over the old foam and the new plywood. The ads online worry me that I am getting some sort of slipcover. I just want the edges to be nicely stitched like the original.