I am in the process of learning how to cut out a car body. I managed to thin the side wall so much that my once flat and square body is now a bit warped. I can now see a gap about the thickness of a sheet of paper under my DFW. I was planning on filling in the now hallow areas of the body with balsa. Would clamping the body down and adding the balsa correct this or is this a lesson on not trimming to much off the side walls?