I don't think anyone is trying to keep any secrets about the color for the girth belt. Plenty of posts have been made about it. I went the minwax route on a couple of my attempts and its all in my build thread. I went with 'crimson' and it worked pretty good color-wise. A dark desaturated red is closer to the real belt than a brown. However, in my experience, I don't recommend the minwax method as it leads to a pretty stiff girth which is both impractical and inaccurate. The real girths were dyed with fabric dyes. I ended up making my own mohair girth, dyed bright red, then given a light dye bath of black and further weathered to desaturate and darken it. But anyway, most of the information you seek is usually on the forum, it's just hard to find because of the linear nature of posting.