[Amps] peak voltage rating for load cap

[Conrad PA5Y]

Hello what is the rule of thumb for conservatively estimating the 
required ratings for a load capacitor when used with a mono band Pi-L 
tank circuit?

Anode voltage 2750V

Tube design RL = 2600 ohms

Q = 12

I have searched on the internet an I cannot find any really convincing 
info, I have something that will stand 1200V but that is marginal and 
will not survive a fault I expect.

Alternatively does anyone have a small vac variable around 40-60pF that 
is around 3 inches/76mm? That will obviously do the job.

Also where can I buy a couple of Ohmite Z-50 chokes in Europe? Anyone 
got one or two that they can spare?

Regards

Conrad PA5Y