Very nice build and paint. Im working on a field campo Zero myself now and it definitively is a challenge to make the field camo appear to be painted by a scale man, and not a giant. You mentioned that you thinned your paint to 50:50 to do the camo, and while I don't spray Tamiya acrylics much, that ratio is still thicker than I would normally spray regular paint (60/40 is my regular mix). What is your "normal" ratio? I have discovered over the years that one can thin paint quite a lot, more so than I ever thought possible before, and get very good results. Even switching thinners (more or less retarder) will affect how the paint looks/behaves. Of course, the thinner the paint is the lower the pressure one generally must use. For my recently purchased MRP paints I lowered the pressure from 15 psi (normal with Tamiya/AK/Mr Hobby) to 8 psi, and played around with the MAC valve on my PS-270 (great, cheap, made in Japan brush), which lowers the volume of air but maintains the pressure.
Anyways, great build of a great subject.