Hey I got some shots for you to see. I don't have any of the chain stay clearance but it's about the same as the seat stay clearance. These tires have awesome side knobs that need to be trimmed to get them to fit like you see here.
Sweet looking bike! I just discovered the term "monster cross" a few days ago after having sold all my bikes but my cross bike and having to use my cross bike as a mtb. At first I didn't like it so much, but now that I feel more dialed I am just loving riding the cross bike on the trails I loved my mtb on. So I started thinking about racing my cross bike as a mtb next year and I just started racing it in crits and it works great! (And, of course I race it in cross!) So anyway, I'm looking for the fattest tires I can fit for mtb racing. I ordered the same you have, the panaracer fire/cross 45mm and if the back won't fit I'll return the rear and look for something 42ish or something. It was your pictures that turned the light on for me. Thanks!