What is the plate load impedance of a pair of 4cx800A tubes run at
2500VDC and 1500 watts out?
I have read varying opinions on the amp groups ranging from 800ohms to
2100 ohms. I thought it might be 1600 ohms.
Once the impedance is known I can try to determine the minimum tuning
capacitance that I need.
The pair of tubes are 22pf. What would be guesstimate of the stray
capacitance in the tank circuit?

I am undecided if I will use Pi or Pi-L network and whether it will be a
load of 50 ohm or 200ohms with a toroid to bring it down to 50 ohms. I
have to use real world parts....

I can use a vacuum cap to keep things simple.
since I am not an engineer, I want to be sure that my guesses are in the
ballpark...

any input would be appreciated.

Last time that I built an amp was over twenty years ago. It was a
4-1000a and I built the Hypersil plate transformer by hand winding it
This time I will have Peter Dahl earn his money.

Jim n2go