Eric, I agree with Taylor, the Manton, or Bailes, both L&R's will work, draw the gun out fullsize, and use the full-size drawings from the Track catalogue. Don't go too small, it's amazing how quick these munchkins grow. My first one I tried one of those cheap .32 cal CVA's, and cut it down. That was one Spring, by the time I had it done around the first of August he had already out grown it. Fortunately with 11 grand kids it is easy to pass down. Good luck with the project.
Bill