Sounds like your project is moving along. I was thinking about how you would insure proper alignment with the husk to the frame?
On my grandfather's shop made mill, it used pipe unions that were not adjustable to connect the husk and frame together, and while that worked ok for the guy who built the mill...he fabricated it to mainly saw cottonwoods and soft woods for barn building, it was not ok for hardwoods like black walnut and pecan.......so my grandfather used piano wire and a turnbuckle to make it E string tight, stretched from one end of the carriage frame to the other, and measured to the blade face. When alignment was perfect, he then drilled a hole in each union, 4 of them, and pinned them with roll pins.
I saw the mill many, many years later, and the pins had been removed and replaced with bolts and shims.