RE: cuttin a hole in a foam wing
The stuff they sell at auto parts stores for body work is probably 6-8 oz and it will work, but will come out a little heavier. As for cutting it, you just have to learn to handle it carefully. An Olfa cutter works well, and can be purchased at a fabric store. This looks like a pizza cutter, but the wheel is razor sharp, and give the cleanest cuts for FG. You will need to get a cutting mat too.