DIY preamp triode tester?

[flood]

i have a LOT of ECC88/E88CCs that i've accumulated over the years, and have decided to sell because i could really use the cash right now. i do have a B&K dynaquik tube tester that will give me a qualitative reading as well as mutual transconductance values, but doesn't measure cathode/plate current in mA, most people want to know this so that they have an idea of how close the triode halves are.

does anybody have a schematic for an ultra-simple single-stage preamp that could possibly also double up as a testing rig? would it be necessary to have variable B+ (e.g., about 150V for 6DJ8/6922 and higher voltages for 12A*7 & co?

i've seen this one, but i don't think it's what i'm after... DIY Preamp

...or am i simply obsessing and can i safely go by the dynamic mutual transconductance reading on the B&K as being sufficient for my needs?

thanks to all in advance!