Mine is fully sheeted and glassed then painted, that is #1, #2 is built to the plans but I'm sure the aft section will be lightened even more then I have built it because it will be covered with, Probably SolarTex then the fellow is going with electric power. #1 will be kind of easier to CG because I'm using an SK .80 with a Bisson Pitts muffler. The Ziroil Build does state his came out way tail heavy, that's why I choose such a heavy power plant. I also have some sub-C battery packs. The build is still straight forward though, nothing hard about it at all.