I enjoyed reading your post. I share your likeness for your Universal AVOmeter. I constantly use something less sophisticated : an not-too-old Radio Shack multimeter with a mirror backed needle that I also resuscitated after putting it aside for decades. I like to see a needle moving instead of the flickering numbers of a modern autoranging meter. And yes, I also had damage from the battery used in the ohms reading, which was left in the instrument for 20 years...
Harvey said: "Time vs. money is a tradeoff everyone makes". This is true, but participants in this TekScopes group we are not big followers of this tradeoff. Otherwise we would not care for old Tektronix equipment but would retire them all and buy very inexpensive modern electronic instruments with much superior performances. We are here because we have the time, and we don't care much about money.
The time invested here gives us SATISFACTION. It is like putting the time to learn to play a Beethoven sonata on an old piano instead of going to Youtube and listen to it performed in the Carnegie Hall.