@autospec Decades ago Tektronix made a curve tracer plug-in for their oscilloscopes. It would display the linearity curve of the tube under test, allowing you to know that it was both statically and dynamically matched to another tube with the same curve. That's the best way to match tubes. Most of the tube matching I've seen simply gives you a static test, which you can obtain from a tube tester. Such a test won't give you any information about how one tube matches another when signal is present.
Fortunately curve tracers are not that complex. Here's a construction article:https://www.instructables.com/Tube-Curve-Tracer/
Fortunately curve tracers are not that complex. Here's a construction article:https://www.instructables.com/Tube-Curve-Tracer/