Thiel Owners

I googled expansive grout and all the top results were for non-explosive demolition grout.

That can’t be right.

If you try the Benchmark, you could consider a pair for either horizontal or vertical biamping.  Just don't bridge them... (see the parallel thread on bridged stereo amps into lower impedances...)

These people like them!
https://parttimeaudiophile.com/2020/05/15/qln-prestige-three-loudspeaker-review/
https://parttimeaudiophile.com/2021/07/25/qln-prestige-one-loudspeakers-review/ [with comments on the five]

This probably isn't relevant, but years ago I had Thiel 3.6's driven by Muse model 175 monoblocks.  On one particular CD, a Chandos recording of Martinu piano sonatas, there was a short passage that always seemed to excite one of the tweeters, causing a clipping-like distortion (amps were far from overdriven).  No other music caused this, and the same passage on the same CD played on several other systems caused no problems.  The exact reason was never discovered.  I moved on to Proac Response 2.5's.