Ekos problem/setup questions

I have an Ekos tonearm with a Grado Sonata on an LP12. It all sits on a Mana stand, and I think everything is set up correctly.

My problem is that on some parts of a record, the arm will vibrate side to side, sort of a shimmy. It manifests itself sonically as a low rumble. This happens most frequently on the wide grooves between songs, and once in a while during songs, I suspect the problem may be tracking weight or VTA. I know that these things have to be dialed in just right, and that the Linn is sensitive to small changes.

I bought my rig used, and I don't have setup manuals. I'd like to be able to adjust VTA and tracking weight a little to see if I can tune the table, but I don't see how to do any of this.

Also, I'd like to adjust the cueing.

I brought the table to a local dealer to purchase a T-Kable and I had her inspect it while it was in. She checked it out and said it ran perfectly. I listened and didn't hear the rumble there, but that resulted in the mistaken belief that isolation was the whole problem. It wasn't at all. Anyway, the cueing used to be too low and she changed it and now it's too high. I saw her do it and I'm pretty confident that I can do it, but if there's anyone who knows how to do the VTA and the tracking weight, I'm guessing that person will also be able to instuct me about the cueing.

Thanks much to any advice givers.

It's the "dreaded Grado wobble". The arm's mass is a little too high for that cartridge. It is a common thing that happens to Grado cartridges when mated with the wrong arm. If a little resonance gets started, then it just gets out of control and wobbles all around. Sometimes it will even jump the groove. No problem with either the cartridge or the arm, just the matchup of them both together. Get a little stiffer compliance cartridge, and you'll be ok. Something around 12-15cu would be good.
Thanks! I'll be posting it for sale soon. Any advice on good matches for the LP-12? I was thinking of that new Argo....
I have a Clearaudio wood virtuoso on my ekos lp/12 and really thihk it mates well and is very reasonably priced (600 w/trade 750 retail).

I have the new Lyra Argo on an Ittok LVIII/LP12 and the sound is wonderful. I think this would be a great cartridge for your Ekos. Contact Peter at Red Trumpet for a good price, below the $1195 retail.