That looks nice Karl!
BigZ, let me know how you get on with the PE work. For my crimes, that used to be one of the areas I covered with my old civvy job with the Big Yellow Box, although on PCB work. In that area, the sharpness of the film image was the most critical - the actual resist coating and etch was fairly straightforward. Of course, the tolerances were much finer than those required for model PE parts, but even so, it's still fine-line work you'll be handling. I'm presuming you'll be using the OHP material as a contact film, so at least one of the possible variables has been removed. Given that the OHP material has good enough resolution, it should work, although I'd expect you'll need a bit of trial and error. Good luck, and let me know the results please.
Terry.