Hey slaw, I guess you have your ET on a VPI, not your Townshend Audio Rock 7, ay? ;-) What arm is on your Rock? My Rock Elite (Mk.2) was made with it’s damping trough having an arc diameter appropriate for the shorter-than-usual Townshend Excalibur arm. The Zeta I use with my Rock is very close to the Excalibur in that regard (pivot-to-stylus distance), but has much better bearings (and a great stiff arm tube).
The Helius Omega arm has found favour amongst UK owners of the Rock 7. The Silver/Ruby version is especially nice, but at a not-so-nice price ;-) . Townshend Audio and Helius just happen to share the same U.S.A. distributor. Tim de Paravicini also recommends the Omega for use on his EAR Disc Master turntable, the table Audiogon member folkfreak owns (I saw and heard it in his music room last year), though he uses different arms (two) on his.