In my opinion, you are not going to get the most out of your speakers trying to use the amps you list. They just cannot supply the current and control these speakers need. If you want to go tubes, IMO you'll need to stay with more powerful models that use larger power supplies and output transformers, and with at least four or more higher-power variety output tubes per channel (probably twice that if using lower-power variety output tubes). To me, this pretty much rules out tubed integrateds, and I think these results will obtain even when listening at low-to-moderate volumes. I say this as a CS2.2 owner who has tried both moderate- and higher-powered tubed power amps (C-J MV-55, VTL MB-185 Sigs.) - and those Thiels aren't even as demanding (impedance-wise and in woofer size, though their sensitivity is similarly moderate) as yours, and my room where I used the smaller amp was also much smaller than yours. Even my newer, larger room, in which I was really forced to move to the higher-powered amps, is not as large as yours is. Also, keep in mind that your speakers are very revealing of amplifier quality, not just quantity, and the lower-priced models you mention will not be shown to their best advantage by speakers which really want top-notch amplification, not just plenty of it.
