Keep in mind @unsound listens very loudly, peaks at 105 dB. Most Thiels are certainly going to need a boatload of power 2-4 ohms to reach that level. If I had that listening preference, I would pick different speakers.
If you listen to Thiels at more typical levels, it opens up many options. IMO, test results of steady state signals are , at best, a guide. It’s fair, I think, to look at the measurements and conclude a 10 W SET is a poor match for the CS5. But there is a wide middle-ground where you might let your ear be your guide. Here are the measurements for my amp which @unsound has informed me is a poor match for the CS2.4 despite, apparently, never having listened to the combo:
https://www.hifinews.com/content/ayre-ax-5-twenty-integrated-amplifier-lab-report