T_bone,
I have made a few adjustments to my system. Having now further customised my arm tower to a weight of 6kg, I also used three spikes to couple it to the platform. However, and I really have no idea why this should be, the real transformation came in removing my Symposium Ultra platform and seating everything directly on my birch wall shelf: WOW!
I can now state that having the tt and arm tower on seperate axis of isolation works. I have owned a few tt's (including the Roksan Xerxes, Roksan Xerxes 10, SME 10, Clear Audio Master Reference and Acoustic Signature Mambo)and a variety of platforms and isolation. Yet I have never had the level of performance that I am currently getting from the nude Technics SP10 MkII with a completely decoupled arm tower. The inner detail, staging, clarity, ease and frequency extention all show major improvements to what I have heard before (outside of live venues of course).
I will continue to experiment with test tracks and human and technological support to confirm or challenge my perceptions. However, I have no axe to grind here but I would hasten to say that this must be tried out. The differences are not subtle!!!