Question for those who use REL subs with Wilson speakers

Question for those of you who have experience using REL subs with Wilson Audio speakers:

I have Wilson Sasha 1s with a pair of S/812s. Love the sound. Before getting the subs, I had considered possibly upgrading in the Wilson line eventually (I had Sophia’s before). However, now I am wondering if it may be more effective in terms of overall sonic improvement to perhaps add a second pair of S/812s or even eventually having 2 stacks of 3 with my Sashas. I am very happy with the sound I have now, so I do not feel like I have to change anything at all; but I am intrigued by this question. Thanks in advance for your opinions.