i don’t have specifics, but if leakage resistance were as low as 1 MΩ, (generally considered poor quality for a capacitor, some having leakage resistance as high as 10^12 Ω),
this would yield self-discharge current of 45 mA at 45kV. If τ0 = RC is the time constant, then a 33,000 μF cap would have τ0 = 33,000.
With these parameters i think we could run a pinch every few minutes without significant loss.
http://en.wikipedia.org/wiki/Types_of_capacitor
