Connect THCAD 300 to HF plasma?

I have 4 or more of the Mesa THCAD 300 connected to HF and HV plasma sources, but for that to work properly there is only 1 or 2 places inside the plasma, namely on the rectifier output or the RC filter board that protects the rectifier from the HV/HF.
Rectifier output is easy to find on tranformer type, not so easy on inverter types.
Also beware that the usuall electric/electronic rules that the clamp cable goes to + and the torch cable goes to - of the rectifier does not apply as there are inductor coils made out of negative wire going to the torch so it will have full 20000 or more volts going to it when pilot arc is active.
Rectifier output is the safest place.
And of course use at your own risk, there is no support for it as clearly stated on the manual.
Use 100 ohm resistors for both leads at the rectifier to prevent having the whole power going through the wires just in case they short to something. They will change a bit the voltage readings but not by much and it will no affect the cutting and usability.

I can take pictures of two transformer type i have here, no inverter type here, the nearest is 110KM far.
I do have a Hypertherm Max 43 that is inverter type but has no torch so not helpful at all.
Never done those Cut thingies, but if you can take some pictures of the innards i might help figuring out the wiring points.