Mmmkay,
I finally had some time to fool around with the proto tube, powered by my CT-100 chassis. I mounted the stuff in the cabinet same as at the museum, then powered it up. Luckily, the tube rim doesn't get close enough to the chassis to arc over with the chassis in the cabinet.
I found that I have the same issue with not being able to achieve convergence, despite the HV pot mod being done. I confirmed that ultor potential is not dancing around, even with the convergence control maxed out. In this shot I haven't really done anything with the static magnets, just powered it up and played with the DC convergence control. Same as at the museum- you can get close, but not close enough. This is with the 'stock' 50 meg string resistors installed in the chassis, next I will give the 100 meg ones a try.
