OK. The new chamber finally arrived along with the 8″ conflat blanks and gaskets:
Right off the bat we have trouble, a nick on the knife edge of the 8″ chamber conflat:
Today I’m going to assemble the chamber and pump, and see how low we can go despite the nick.
The next step would be to weld on a fresh conflat.
Prometheus Fusion Perfection 
going to have to wait for some nuts and bolts to arrive first.