[Boatanchors] testing 0A2 tubes?

[Eugene Hertz]

Hello all, while trying to troubleshoot a possible regulation problem in a transmitter, I decided to test my 0A2 tube in my tester which is an I-177-B military thingy.  Apparently, the test it can do is limited and they caution that this is only a partial test.  However, the results are bizzare! So I thought my tube was bad because it tested around 500 (on the scale, however I dont think its micromhos that its reading for 0A2 tubes) but the needle would bounce around terribly while pressing the "GAS 1" button. With each purple flash in the tube, the needle jumped sometimes to zero. I even let the gas1 test stay on for 1 minute or so in case there was warm up involved. 

So I decided to buy some more tubes. I bought a bunch on ebay from a seller who has VG feedback and said the tubes were used but tested strong.  However on my tester, one was nearly a dud (scoring less than 50 on the scale) others seemed very weak and "bouncy" while only 2 were "strong >500" and stable.

What does it all mean? Is stability of the needle something that is good or indifferent? The manual says >200 is good, but is 1000 better than 200 or is a tube like this either good or bad with no in between?

Is there a better way to test these things? Should I throw out this tube tester and get something "better?"

thanks
Eugene