k, this is from Terry over guitar amplifier pcbs:
"Version 2.3 of the Baby Will uses two 100 ohm 1% resistors to create a DC elevated artificial center tap. They run from each of the heater traces to the power tubes' cathode with operates at around +10Vdc, thus the dc elevation.
So the hum balance pot isn't necessary for version 2.3. It's much simpler this way.
I hope this helps.
I have those in already, so I'm resoldering them and shortening the leads.