Samhar...I believe Taters has the VT100MkIII which is easier to bias than Mk I and II (see Davemitchell's comment above).
Taters...I agree with Samhar that you should be a bit more careful that this tech guy is going to put in appropriate tubes. There is nothing wrong with getting him to do it as long as you know he is getting 2 sets of matched quads or a matched octet of 6550s. I would also agree that yo want to make sure the 6922 input/driver tubes (especially the driver tubes) are up to spec. So I would tell the Tech guy that you want to be present when he retubes your amp so you can learn how to check and maintain it going forward. And if he says ok, then you want to make sure that he tests the tubes in front of you and explains toyou that the tubes are testing well and that he then shows you how to check bias measurements and to adjust bias after retubing the unit. If he is ok with that, you then can personally verify that things are being done to spec and you are learning how to do it for yourself going forward. My 2c worth
Taters...I agree with Samhar that you should be a bit more careful that this tech guy is going to put in appropriate tubes. There is nothing wrong with getting him to do it as long as you know he is getting 2 sets of matched quads or a matched octet of 6550s. I would also agree that yo want to make sure the 6922 input/driver tubes (especially the driver tubes) are up to spec. So I would tell the Tech guy that you want to be present when he retubes your amp so you can learn how to check and maintain it going forward. And if he says ok, then you want to make sure that he tests the tubes in front of you and explains toyou that the tubes are testing well and that he then shows you how to check bias measurements and to adjust bias after retubing the unit. If he is ok with that, you then can personally verify that things are being done to spec and you are learning how to do it for yourself going forward. My 2c worth