I try to always get Left / Right matched tubes whenever possible to ensure or hopefully ensure perfect channel balance
With tubes like 6922 I also try to get matched triodes
I just picked up a tube tester , mostly to prevent any bad tubes getting into my equipment. I was up until midnight learning how to use it. Was able to compare it to known values on new amplitrex and Apex matched tubes and it is extremely close to their readings. I was the one guy on eBay this week that didn’t get screwed buying a tube tester.