Does anyone have any experience with the Bear Paw Wilderness Designs bathtub floor? I just spent a night out in the woods this past weekend and my homemade tyvek ground cloth finally gave way. I was just abought to buy some polycryo ground cloth from Gossamer Gear and then a friend at work mentioned the bathtub floor. I use the ground cloth under a Outdoor Research Helium Bivy with a tarp setup over the bivy. Any suggestions on a new ground cloth would be much appreciated.