We used plastic on side two.

The plastic sheeting did a pretty good job of giving a smooth surface in the areas where we could get it to smooth out. I think the next time we use it we will use smaller pieces to get it to form to any curves better. We had wrinkles and the rankles made ridges that will need more sanding. In all the application of the plastic smoothed most of the bottom and will save a lot of sanding later.