Thiel Owners

Much of the spike length was intended for carpet height piercing.

The outriggers and spikes on my CS2.4SE raise the speakers a good 2". I think these spikes are a bit longer compared to the standard version. About one-half of my floor is slab and tile with a hand-woven rug under the speakers. I use 1.5 x 2 x 0.25" wood blocks under the spikes to protect the rug. The other half, which includes my listening seat, has wall-to-wall on top of the slab. I find the spikes to improve the SQ at least a little altho' not sure how much is due to listening height v. better coupling to the floor.

limited to perhaps 200 Hz and above.

Yes, Thiel's graphs are truncated at 200 cycles:
http://www.vandersteen.com/media/files/APJ%20Files/APJ_6-7r.pdf

Those CS2.3 measurements are superb!

For the bass, I think Stereophile's nearfield technique fills in the gap nicely.

"The outriggers and spikes on my CS2.4SE raise the speakers a good 2""

That's one reason I haven't used mine.  Even raising my speakers on shorter footers has changed the sound in a way I don't care for.

Prof, What’s your distance from speaker to seated listening position?