First off, take all such comments with a grain of salt. What does it really mean when Joe Blow Guitar-god comes online and claims Tube-X is "better" than some other? He likes it better, OK fine. DO you have the same taste in tone as he? Is his amp identical to yours? Does he play the same guitar and pickups? Same speaker? AT best it is a suggestion. It is like someone saying lobster is better than steak. Maybe for some guys it is, but for others it ain't.
What makes tubes sound different? SUbtle differences in the internal element spacing, slight differences in interelement capacitances, maybe some cathodic material differences. whatever.
Depending upon the circuit and how you play through the amp, you may or may not notice a lot of difference.
To me, the tube differences are about on the order of the differences betwen brands of guitar strings.
Remember that NOS doesn;t specify any particular tube, it just means old tubes that have not been used.
And remember also, that each socket in the amp does a different job. There are inoput stages, tone stack recovery stages, phase inverter stages, and reverbs and trems, and other things. SOme amps have extra tube stages added in for OD channels, while others use separate channel paths.
Really, ther is no scientific procedure for netting your tone from tube specs. You get yourself a selection of tubes, and pick a socket. Try the various tubes in that socket. You may or may not notice a lot of difference. If you do, great, use the tube you lihe. Then move to the next socket. DO it all again.
Hit or miss? Maybe. Or maybe it is like going to the same restaurant and trying a diferent entree each time. The tubes you don;t use will be fine as spares. Can you tie up $100 in tubes? Sure, but that is the price of glory.
This is of course just my opinion, others may disagree.