I love polymax, but don't like to span it more than 8" and i still am careful where i step. If you don't have a double rail frame, it is 't going to hold up. It sure is nice to keep the weight down, and gives great grip for the dogs. On my first raft i just did a small fore/aft bar like a second rail, but only in the cockpit. I still dis somethi g to support on the front/rear bays too. But this way i didn't need a full double rail. Drawback- you can no longer adjust the size of the cockpit. Personally i get tired of wood, and if i were going to do something else i'd do metal.
Living in Montana, boating in Idaho