RE: GP extra 300s build
t-max, I suggested the Ultracote because I found it to be easier to get good results and seems to hold a non wrinkled finish better than the Monocrap. I used to be a "monocrap guy" but after covering K C's plane with Ultracote I am sold on it. Use what ever you want to try so you know for yourself what works best. BTY, I also have covered a biplane with Towerkote and liked it. It went on nice, shrunk up well, and has held up without wrinkling (low price too). Color selection is limited with Towerkote however, just basic colors. Keep pluging along, your doing fine.