Next step is extremely important. The downside to using a water based product like Min Wax is potential warping. If the silkspan is being applied to a balsa/foam sheeted wing you likely won't have a problem. I did two Proteus builds with Dave Snow built up wings and learned the hard way. On the areas that had large bays, I had some rippling of the surface. On the second Proteus, I controlled it and didn't have a problem.

The way I control it is to use two or three thinned coats of lacquer. Lacquer sanding sealer will work as well. On this build, the only area I used lacquer was on the ailerons. Trust me. if you don't seal the ailerons, they will warp. Ailerons may still warp just a bit even if they are sealed. If they do, I put a coat of Min Wax on the back side of the surface, weight it and it will be fine.