Thermistor With Hybrid Greatz

[wobbly]

I am researching a power supply for a 300b project.
The basics are 420V at 180mA via a GZ34 hybrid greatz bridge.
This will drive a E choke as designed by VanDerveen and sold by TentLabs.
The tech info calculation for this E choke to maintain regulation requires 120uF at the circuit input.
A GZ34 lists a max of 60uF, so my idea was to fit a NTC Thermistor in the line from the bridge to the first cap, to limit the current surge at switch on.
This would allow the correct value of cap needed to meet the E choke input ripple spec, and protect the tube.
I have read alot of literature but just cant get a handle on how to spec a thermistor to do this job - can anyone point me in the right direction.
Thanks