Forget all about rejuvinating. That CRT is not likely to respond like a TV CRT.

I couldn't get a real print on it but most of these things have a DC filament supply which is rectified off the flyback. Note that they are turned and the fast sweep is vertical and the slow sweep is horizontal. Just imagine the two deflection circuits swapped.

As such, off the flyback (VERTICAL OUTPUT) there should be a winding for the filament supply. There may be a filter going dry.

If the supply is alright, there is the place you put a tertiary coil in series with the winding to boost the voltage.

As far as what the voltages actually are, if the geometry is correct, the voltages are probably correct.

Rejuvination is a last resort on something like this. Even if you can get a CRT for it, the alignment is hairy and scary.