I have heard these in dealer showrooms and in a few friend's homes. They sound good and have a great reputation.
I think the Sunfire 300~2 might be a great match for your Thiels. Based on the 1.6s taste for mellow tube amp power, I would use the "current source" speaker post connections, rather than the voltage posts.
Please let us know how the bottom end sounds once you get these up and running to your liking. .