I use System Three and agree with Dwight and Mike. If you have the time use the slow hardner at higher temperatures. It's thinner and self levels better, but it also runs more. Solution: get the foam roller covers from System Three, but use them to spread (like using a squeegee) the resin, no roller frame. Wear gloves for this. You can spread the resin so thin, its hard to tell it's there. Or any thickness you want. The roller also bridges hollow spots to help level them. This method also produces fewer bubbles than rolling, which I tip off with a brush. The rollers can cut in half and cut in half again lenghtwise to give four "foam" squeegees. If you have significant hollows try leveling the boat in that area and fill them first. The resin will self level and additional fill coats will blend it all together. Happy Sanding, Jerry