Re:
Mark, it's a 44mm headtube and has a Hope headset fitted,with the same Lefty kit that you use.
It was actually seeing your Skookum that gave me the idea for this build.
I am nearly 6' 2" tall, with a 35" inside leg so it needed to be fairly big.
The only bike to ever fit me perfectly was my Pace RC200 20" which unfortunately fell in half in February and this is loosely based on the dimensions of that so hopefully will feel as good, but with decent suspension and brakes that work.
I liked the idea of belt drive but have seen a couple of broken ones and I want this to be ultra reliable above almost anything else.