Go to
www.parmodels.com for almost all the old Jigtime and Goldberg rubber band kits. Free downloadable files. You can them scale them to whatever size you want. If you print directly on balsa, you even get all the decorations!
BTW, Paul still needs a copy of the Spitfire Jigtime kit and the Midwest Cardinal kit to complete the set. He would buy or borrow. I have loaned him kits and they come back in perfect condition. He is currently generating the plan to the P-51 from a built model! Not an easy task, I expect.