Isolation Platform for my Sota Cosmos?

The fly in the ointment when using suspended turntables on isolation devices such as Vibraplane is that if the resonant frequency of the turntable's suspension is close to that of the isolating system the two systems can interfere with each other. Like a car going down the street with two shock absorbers for each wheel, linked in series. The passengers in the car will have a very bumpy ride. One way to test this theory is to disengage the turntable suspension and see wa' happen.

The Vibraplane and the VPI towers are almost certainly not tuned to the same resonant freq. The Vibraplane is most likely around 2.5 Hz in vertical, I suspect the VPI towers' resonant frequency is around 4 or 5 Hz, possibly higher. Even though the resonant frequencies are not equal the two systems can still interfere, when you consider the mass on spring device acts as low pass filter with attenuation characteristics analogous to electronic filter, E.g., 6 dB per octave. So they can still interfere.