I just built my trainer from a kit and covered it in Ultracote. It takes time and practice but I didn't find it too difficult. I was thinking I did an alright job but still had a few wrinkles. Then I saw my Uncle's Avistar ARF. The covering had bubbles all over the tail fins and some visible seems. Wrinkles all over the wing. All stuff that he could take an iron or heat gun to and fix but it made me feel alot better about my covering job. My advice would be to go for it with ultracote. If it doesn't come out right you can always rip it off and start over. (Had to do that a few times, lol)