i'd start with a full retube, and roll. only thing i've ever had to deal with with any of mine was worn tubes in thousands of hours, and one solder joint that i broke on a knob 'cause i overtightened a collar nut due to my own derp. :D
just bought an '81 iib myself in december, retubed and...
i dunno.. i run my volume 1 on my '81 mark iib on about 2-3, and push my master volume up high as i can get away with- seems like for around the house northwards of 3. it can be squeaky clean, for sure that way.
mines set basically input 2-3 (bright pulled)/treble (not pulled) 10/bass...
well, HCAF beat you gents to the punch. if any of you cats are looking--- here's a great document of this mod-- and i'll have better information from the mesa techs as of thursday, so i'll post any pertinent information then...
hey gents-- did a quick search for this, but didn't find the gain control mod for the lead channel.
love my .22.. but lead's got TOO much gain for me-- anybody have a link-- google and the search menu here have let me down!
thanks much!