[Electronic M]

I'd try to stop the arcing first. Generally shorting does not cause arcing as it usually loads the flyback and luggs down the voltage. Case in point I have a Panasonic hybrid that had an oil filled cap on the flyback short and it didn't make any HV or arcing, and the H output tube was redplating like mad despite having plenty of drive from the osc.

Arcing is normally either the result of failing insulation, conductive dirt bypassing insulation, or excessive HV.