[Eliot Ness]

One more question about the AK 20 Big Box set: I have just finished putting the AES power supply kit together, and when I measured the outputs on the 'B' terminals, the 90 was just under at 88v, but the 22 was higher at 23.5. Should I add a small resistor to the 22 terminal to bring it down to 22.5? I have a fear of hurting a 201a tube.

No, you should be fine with those voltages.  The 23.5 will probably drop a little when you hook it up anyway.  Back when the set was new those voltages were not that precise because of the batteries, eliminators, chargers, etc..  I would verify the A voltage going to the filiments before hooking up the power supply.