Croft Super Micro meets Acoustat TNT200

[billa]

Hello DIY fans,

I'm just changing power amps from a Sugden AU51P to a Acoustat TNT200 and I want to match the input impedance of the TNT200 to the output impedance of my Croft Super Micro - hopefully to give best power throughput / sound.
Can I please ask a few amateur questions?

What are the current output impedance of the Croft and input impedance of the TNT200? (I have no manuals).

How can one measure the values?

There is a specification for doing output impedance for a car amplifier at http://www.bcae1.com/outptimp.htm and a circuit for the Croft at http://www.soton.ac.uk/~apm3/diyaudi...I_circuit.gif. I can't see anything for thr TNT200's input impedance.

How would one change the output impedance of the Croft. I assume it would be done in the circuit after the ECC82? or is this a function of the valve itself?

Totally seperately does anyone know a source of high quality (e.g. PEC, Alps) 1M ohm pots as I can't find anything at that value and mine are "crunchy".

TIA
Bill