Andy
While your still in the wood removal stage, you might want to consider removing the "fish belly" curve from the bottom of the butt.
If this area is changed from a bulging curve to a straight line between the wrist and the butt plate, the gun's appearance will be quite close to a real Hawken rifle.
Of course, if you're like several others I know, looking like a Hawken isn't that important but changing the shape is something to think about.
I've been looking at a bunch of picture of originals and will try to make it as close as I can. My biggest concern is the cheek piece, the one that Lyman puts on is huge and coyote ugly it's going to take a lot of work to make that look good.