Both your initial 2 amps and now your expanded list all appear to be good tube amp examples. For your goals of warmer, fatter midrange, a lower wattage SET amp would probably provide more obvious differences in those attributes and take advantage of your ability to go low watts with the sensitive Klipsch’s. Probably going to be tough to beat a Willsenton for bang for your buck, especially used. If you start doing upgrades or getting expensive 300b tubes though that initial low cost can vanish. There are other SET tube options with less pricy tubes that are also very good. A more off the beaten path option (though popular) would be a used, already built Elekit if your main priority is sound quality, and not a remote, a lot of inputs, or highly polished looks. I can speak for the TU-8500 with 6L6 and many other similar tube types compatibility for rolling. It compares very favorably with more expensive SETs and you’d have to spend much more for better sound quality. Typical used price can be a little less than the original parts kit cost. My TU-8500 purchased at $750 keeps up with much more expensive SETs that I have had in my system. You can keep an eye out for the ones with the upgraded Lundahl transformers. Also second Erhard suggestion - the 4 WPC Ray 6L6 SET model. Would have to be new since they don’t show up used, but reasonably priced new especially considering hand built in the U.S.
