prof,
I have a different take on spiking Thiels. I don't know if the 2.4, 2.7, 3.7 have a better system/ outriggers as mentioned earlier, but the 3.5s just had holes in the base that accepted the provided spikes.
Shortly after getting my 3.5s; "Sound Anchor" came out with dedicated stands for the 3.5s. I bought a pair and never looked back. You could use the new threaded spikes that came with the stands or use any spike you desired or Stillpoints of today. The benefit was not subtle. The other benefit was that you could finally level and plumb the Speakers. A not subtle benefit.
I tried tilting various speakers over the years but the Thiels are time aligned already. You can try it as robinbarbour suggests. Personally I think Speakers are designed to be setup symmetrically, level and plumb. The more precise; The better. Hence, my use of a laser since Jim Smiths book. 1/16" accuracy. Another; Not Subtle benefit.
Any height difference due to spikes plus stands can be made up at the listening position.
Sound Anchor is still in business. I also had a pair of their stands for a pair of Wilson "Cubs" Anyway, very well made and beneficial to bass, soundstage and imaging.
A lot of listening and moving Speakers and more listening is enjoyable work , but still work .
If you are able; Take your time.
Best to you
Norb