Speaker Connectors: Banana Plug conversion adaptor to spades

Black Cat Cable sells the XOX spade to banana adapter for that purpose. Thet sell two versions, the Reference and the Studio. Check them out.

I have a similar question, am curious if either of these adapters (both still available in Jan 2020) worked on the Thiel's.  It's mighty tight at the bottom where the connections are, one of my least favorite things about otherwise great speakers.

I actually learned that I was incorrect in thinking my Thiel's would only accept spades.  I had previously encountered speaker's whose mounting post knob had a plug in them that was easily removed.  What I discovered with my Thiels is I had to completely unscrew & remove the mounting post knob & punch the plug out through the bottom. 

So, I was wrong & I suspect that you have the same situation as I had.