Cool design too, Mich! Is that a real Altec meter, or a re-purposed Jewell MM2? Funny, they still make that same old meter.
The Jewell meter was from surplus sales and had a reverse scale, too hard to reverse it, so I hacked the back and fitted a 100uA movement. Downloaded hi res picture of original off the web and printed the scale and stuck it on original faceplate. It works fine and is just a visual indication of whats going on anyway.
I fitted the extra tube, not only for the stability, but because I didn't have the correct input TX. According to one of CJ's tear-downs the original is a step-up of about 1:2.5 (don't quote me, read the thread) so I was going to be short of gain compared to the original. Abbey Road must have changed it too because they used a 200 Ohm standard in their studio.