Oppinions on dealing with a 3DS3 HV rectifier

[Electronic M]

I'm working on a GE C2 chassis clone....revisiting since I found a C1 schematic among my literature that gave me some usefull info in the horizontal circuit to troubleshoot a NO HV issue....

Anyway my B&K 606 does not seem to have settings for the weird 3DS3 rectifier (which has a shield built in to the bulb)....I've found that my H output tube is getting the correct drive and voltages, and that the top cap of the rectifier gives a healthy arc, but I'm only getting 8-12KV (should be 22KV) out of it.

I think the tube is bad, but I can't test it and I don't have another to sub (and the socket wiring is different from the 3V HV rects I do have).... My question is does anyone think it would be alright to rewire the socket for something like a 3A3? I don't really feel like coughing up $6 for another 3DS3...Especially when I don't know for sure that it is the problem. There is no back on the HV cage BTW.