I suggest getting as much bass as you can. IMHO, Thiel's might sometimes sound a bit tilted up without lower octave support.
With the various Thiel's models I think you'll find that the heights of the cabinets vary more than the actual footprints. IMHO, the sloping baffles tend make the cabinets less visually obtrusive.
Something to keep in mind with Thiel's is that in order to appreciate all that Thiel's offer; one must be cognizant of placement and listening position.
I'm firmly in the camp of amps for speakers, not speakers for amps, and perhaps even more so with Thiel's.