You have a typo on your voltage range. If you meant .030 - .035VDC, then that is similar number value that EL34 prefers for bias current, 30-35mA. So you could assume that IF 6550/KT88 types are allowed in this amp (make sure - rtfm,) then the voltage bias setting for those would be 60-75mA, or .060 - .075VDC, per manual. But that is a lot more current than the EL34s require, so the PS must be designed to handle it, or else your main fuse will blow.
As for the bias procedure, it's usually something like this:
Let the amp fully warm up, minimum 15 minutes or more. Everything, even iron core transformers should be fully hot. Mute input signal. Connect your meter to the test points. Adjust the bias pots to the recommended setting. Check that all the pots are correct, as sometimes turning up one pot will rob from a previously adjusted pot. Once they are all stable and same value to spec, then you are done. Disconnect meter, install tube guard, pour a nice red, put on John Coltrane's "Lush Life."
If you are replacing tubes, or tube rolling it is more complicated:
Power on the amp with the old tubes still installed. Connect meter to test points and turn down the bias adjustment pot to minimum setting, using the meter to verify that you are at zero, and not full high. Some amps are fully clockwise, some are fully counterclockwise to achieve zero bias current. Never guess, never remember from last year, always check it. Tubes are expensive! Turning on the amp with full bias will fry the new tubes quickly. Once all bias pots are set to zero, then power off the amp, replace tubes, power on, warm up, slowly crank in 90% of the Cayin recommended bias setting. The meter reading will move up slower than the screw cranks, so you have to go slow, so you don't overshoot. Once you have all bias pots up to 90% and all measurements are stable, then bring them to 100%. With brand new unburned tubes leave meter connected for 30-60 minutes to make slight adjustments as they burn in. Then check it again after playing music for 1 day, 1 week, 1 month, then however often you prefer, probably 3-6 months. For JJ, or vintage 3 months, for New Sensor or high quality chinese 6 months.
