Sorry Peterae - i didnt see that - so your doing this as a one shot.If you had a lot of hv in reserve capacity how fast could you cycle the output stage?
If it s squeeling it is most likley punched throughWhen you unloaded your supply - big volts - big amps - many turns - the pulse on the output side may have been 40kv 50kv?can you run your supply from a battery?