There is no problem in general with manual bias. To my way of thinking having to turn the unit upside down and taking the bottom off to reach the bias pots is prehistoric. Even my 40 or 50 year old Dynaco ST70 has the bias adjustments performed from the top of the unit, without exposure to other rather lethal areas of the amp.
Place the multimeter probes on the amp, turn the bias screw to the correct reading, or a little less than the manual recommends as oldhvymec alludes to, and done in 5 seconds.