ORIGINAL: Bigboat
Our HV-coil makes about 400 till 600 Volt, depent how the coil is wind and how the ocsilator is working.
Raisetime untill 150 Volt less than 3ms, 400 till 600 Volt within 3ms
I have just downloaded a simulation program for the Linear LT3750 and I set the cap to 470nF and the result is charge time 0.6ms to 150V and 2.9ms to 400V, so it looks promising.