I agree with Jim on this, and want to add that the best tube tester I've ever found is my own VTA70 amplifier.
I've bought and sold 4 tubes testers over the past ten years, dont' need them.
I can tell at a glance how close the tubes are, and 90% of the time just buying a set of unmatched tubes and putting them in the amp,
they are usually within 5-10%, on the other hand, sometimes you get an odd tube that is 20-30% off from the others.
Buying a matched pair or quad is easy and cheap, but you can also do your own tube matching with the amp.
Just install the tubes, and watch where the bias pots end up at once you've got the cathode bias readings matched.
If you're a "numbers" person and you need a number, once they are matched for bias reading, just go ahead and read the grid voltage off the output cap that goes to that tube.
Then you'll know the plate voltage (the amp B+, which in the VTA70 is around 420vdc), the grid voltage (usually around -40vdc), and the cathode bias (0.400vdc recommended).
And it never hurts to buy an extra tube or an extra pair of tubes. Out of six tubes I'd be amazed if you didn't find 4 that were a near perfect match.