How do you guys mark cross section lines, for example, panel lines or invasions stripes on a tapered fuse on a scale war bird? You can't just lay a flexible ruler down and draw. The line will come out curved. I experimented with a homemade height gage once that I made out of some wooden yard sticks, but had limited success. That's why I'm throwing this one out to all you building experts out there. Thanks for lookin'! David