Thanks. I have no idea if an arm could be sibilant. In my ignorance I assume sibilance is distortion and I know that tonearms vary in terms of distortion level. I struggled with sibilance with my Trident tonearm to the point where I just assumed it was a thing to accept with analog but when I switched to Black Beauty (different table at same time mind you) I never heard sibilance again (that I can recall anyway). Ironically perfect setup with the Black Beauty is, in my opinion, impossible so it's a little strange that it was so clean.
There is also the possibility that the RCA connection scheme of the SME cable is allowing vibrations to travel up to the suspended platform of the Kronos. With the Black Beauty, the RCA connection is on the base of the turntable and there is a very lightweight wires that travel from the suspended platform to the RCA outputs.
Well here's to hoping that it's just setup. I'm not in a rush to find out as I'm too busy enjoying the sound as it is.