I had to add a thin balsa shim to the wing saddle, then I used C/A with baking soda to fill everything in. I used C/A on the FG tape. Do everything in order when assembling the horizonal stab and elevators. Several people have forgotten to insert the elevator halves. I mounted the servos into the hatches with wood screws instead of dinking with the servo rails. It's your choice though. They fly great. I've been flying mine for over a year. I used a Sullivan tail gear in lieu of the supplied wire thingy.