Questions are : I plan on buying several sets of tubes for these amps by different manufacturers. When i have found the ones that i feel i like the best how do i sell the others that will have had an hours worth of use ?
Good question, and one that I've never really felt comfortable with. Since I only buy tubes from folks with tube testers and ratings, I've never felt comfortable enough to sell them after I have used them, since I don't have any calibrated testing equipment. Especially since you are taking someone else's word for their condition before you even used them. Now if you bought them from a reputable dealer, like Vintage Tube Services, Upscale Audio, etc., you may be able to report that they were from these guys, had an hour or two of use, and sell them.
However, if you bought them from a relatively unknown re-seller who happens to have a tube tester, you really don't know how accurate or calibrated their equipment is to start with.
Having never felt comfortable with this predicament is probably why I've never sold any tubes that I've purchased. I don't have enough tubes to bother going out and buying a calibrated tube tester, so I cannot verify the tubes condition, so I do not bother to sell.
They just pile up. :)