I need advice on slider construction

I went to OWC for the first time last week. It was awesome. Now i have the itch to build something similar to their picnic table. Basically a box 3 ft tall X 3 or 4 ft wide, and 30 ft long. It looked to me like they used metal for the frame, and then covered it with material similar to what they use on snowboard sliders. At OWC they also had "wings" on each side. I dont know if these are for added stability or just a different way to hit it. I was thinking of leaving them off. My friend is a welded and he will weld a frame if thats the material we decide to use. On the top I was going to either use the same material as OWC or Trex decking. The sides would be plywood. It has to float, so Ill use either barrels or dock floats. I just want any input before we start building it. It has to be well built and nice, as it will have my companies logo, and another companies logo on it. Nothing ghetto. I plan on making it in two pieces which bolt together for ease of launch and trailering. If it works out, you guys will be welcome to hit it. All you have to do is attend a Midwest Militia event on the Illinois. Any advice would be great.

It will float fine with out the side skirts, Just put your floatation on the outside edges for stability, but shouldn't have stability issues if its that big. The biggest deal it anchoring it down so it doesn't move around while its in the water. Trex is cheaper and its what all the pros use, so you know it works.