@ Dan,
The Bison is going to be a real show stopper my friend. You've taken to vac building like a duck to water.
@Des,
Scott's reply is spot on my old friend. You should try one of these vacuforms,absolutely no doubt you would produce another Master Piece. The only problem you may have is locating a WWI vac kit in 1/32 scale as they are very rare currently. However 1/48 and 1/72 scale WWI are relatively easy to find. E-Bay tended to be an excellent place to find them. If you wished to try an off topic build there are numerous 1/32 scale kits available. As a bonus some of these kits are Biplanes from the between War and WWII era.If you or anyone else would like a link to the suppliers I've dealt with just PM me and I'll sent them to you.
Highest Regards,
Gregory Jouette