When you have odd shapes to fill, always try to think of an alternative way to do it. Sometimes, you can even apply body filler and barely even have to sand it. Here are some ideas:
•Maybe it’s using a bigger piece of thin spring steel for a curve or radius. (.010” thin)
•Maybe it’s using a pvc pipe for something round,
•Maybe it’s using a piece of c-channel to help you get a really straight line.
•Maybe it’s using some of these pieces as a mold to spread filler up to.
Think of this as an idea. If you had the inside of a bead to fill and make perfect. You could spread filler in the bead, and while it’s still wet, take an appropriate sized tube, and push it into the filler. If you let it dry, and pop the tube out, you’ll have a perfectly round and straight bead. (Put tape on the tube first so it comes out of the filler).
Already try to think of there might be a faster and more accurate way to do some of your body work.