Should be flat Shawn, that sheet of marble helps. I use a sheet of thick glass on my table saw table, which right now has a piece of carbon - Divinicil - carbon vacuum bagged to it. I like the idea of iron on film for the wings and tail for weight reasons. That being said, you have seen the junk I fly, it is light but not likely to win any beauty contests. On your plane, paint will probably be another half pound when it is all said and done?? Significant, even if it is not as pretty.
You going to put a real engine on this thing, or is it still going to be one of those battery powered things like we had when we were like 7 or so???????????????
Scott