Helius Omega: Standard vs. Ruby & Silver?

Not that I can or would spend $5000 on a tone arm, but has anyone heard both versions of the Omega? Robert Levi tells me it is THE arm for Decca/Londons. Anyone know it's effective mass? You would think Helius would publish so important a spec, but nope. And Dan Meinwald is, as usual, no help.
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