Fisher SA300 biasing

Does anybody have any experience setting all of the power tube biases on this amp? The service sheet I was able to download doesn't have any bias currents or voltages listed, only a table of resistances for each valve's pins. There are 7 trim pots in there, one for each channel: hum balance, ac balance and dc balance, the seventh pot is for the power supply's -25v voltage, that's the only one that I understand. I was hoping for an easier way to do this other than calculations after reading from a resistor.
I would recommend finding an electronics-tech in your area.
I am certainly no expert in re: to tube electronics, but it sounds like an oscilloscope would be the most accurate way to take readings.
Guitar tube amps often have a hum balance pot which is adjusted by ear for lowest level of hum coming through at the output.
My suspicion is that when these amps were made, there were fewer sources offering matched pairs of output tubes-so if one tube in a pair failed, the ac and dc balance would help to compensate for differences in individual tube characteristics.
If you can find an experienced guitar tube amp builder or amp-tech, that might be a good starting point.
Thanks. Since I last posted, I've read up and think a dual trace scope isn't an unreasonable instrument to own and is perhaps the only way to get this amp perfectly aligned. I think Fisher had a precision amp in mind when it was designed, and although other users have been able to "rough them in" at first, they found that using a scope turned out to be the best way to get this amp to realize it's potential. I rather like the idea that Fisher put so many adjustments in there in the first place.