Chet I am finishing a very long project that is coach built like your 29 Plymouth. After looking back on it I would not have tried so desperately to follow the exact contour of the different pieces of wood. It finally occurred to me that I could have built my own vehicle as long as the metal sheets fit in place. And I could have built it much quicker. I finally started using heavy duty Permatex clear RTV to glue the metal sheets in place. Those guys 80 odd years ago had a lot more skill and patience than I do. A lot more. It's going together fine and yes I did use some small nails to position the steel. Nobody will every know (except you guys) that I resorted to 21st century technology. I also used carpenter's water proof glue Ina lot of places even though there was no evidence of any being originally. I think we over think the originality of the construction of these vehicles don't use the more modern methods and materials available to us . if I was to do this vehicle over again I could lop off several years I'm sure. Just my 2cents. Been there,done that.