Stillpoints Ultra and Wilson Sophia II

I am very intrigued by the new stainless steel and aluminum Ultras fron Stillpoints. So, my questions are these:

1. Have any Sophia owners tried either version under your speakers? If so, what are your thoughts as to the impact of the Ultras on overall presentation?

2. Of those that have tried the Ultras, have you had occasion to compare the stainless steel to the aluminum version? If so, how would you characterize the difference between the two? I am inclined to think that the aluminum could thin out the sound and may take away from the bass, but that purely is supposition. Besides, my speakers are sitting on the Wilson spikes on hardwood floors so I am inclined to think that the stainless steel are the most viable option for me.

3. What size adapter did you use and did you attached the ultras directly to the body of the speaker or to the existing feet where the spikes screw in?

Thanks in advance. Any and all thoughts are appreciated.