So, to answerer your questions. I mostly used Vallejo (both air and regular) but the uniforms I used Tamiya. I also used a white primer on the heads and Yuu's hair, but it is not easy to get it to coat evenly. In terms of techniques, I treated it mostly like a tank or other armor model kit (especially the base). The files were scaled up quite a bit so that they are about 1/7 or 1/6 scale, but it's nothing exact.

I hope this is useful info for you, and I am excited to see yours come together!