New LP12, I like some things and some I don't.

Original LP12:
Pre-Cirkus bearing
Ittok II
Older base with no corner braces.

New LP12:
Early Ekos
Corner braced base

I transferred my my Benz M2 Wood body cart to the new table.
At first the midrange was very forward & shouting. Bass was better defined but weaker. I recall people saying the Trampoline was not good if your table is on a wall shelf like mine, so I removed it and put the stock feet and bottom cover on instead.
Much better, bass was strong & well defined, imaging was wider, the midrange backed off some, but is still too forward.

Does anyone have an opinion about what to do to get the midrange to relax? I still have my old table and can mix match parts if necessary. I think the sound I'm not liking may be due to the Cirkus bearing?
Have you tried it without the bottom cover off? Many people find the sound to be more satisfying with the bottom open.
Sorry to say, but I have never been a fan of the cirkus bearing. To me, it always made it sound more "digital" and lost the magic of the LP12. Removing the trampoline is a step in the right direction in my opinion.
I would also check to see if the top plate "rattles" in either corner, near the switch and near the motor. I have experienced that and it makes it sound very "shouty", especially in the upper midrange. If you rap on it with your finger you can see how solid the fitting is.
I don't know if this will solve your "problem", but I got good results from using Mapleshade's rubber/cork/rubber footers under their 2-inch maple with 3 triple-point brass cones under my Lingo 1(those triple-points are a pain to set up). I no longer desire a Lingo 2. I also believe the current Linn mat is much better than the old(circa 1992) mat. If you were using an Archiv, I would recommend their Linto step-up(soon to try reference points under, with the maple and r/c/r footers). I use a Mana Reference Table with the bottom plate removed from the Linn, but I have heard that a wall shelf is almost optimal. I have read that some people prefer pre-cirkus. Probably putting the r/c/r footers and Mapleshade's 2-inch maple under the Linn would eliminate the midrange problem, and I did that to good effect on an Ariston RD110, but it might diminish some of the qualities that you bought the Linn for.
Hello, you also may want to check to make sure things aren't overtightened, especially the strap that mounts the power supply board. LP12s, like any other 'table, sound like bad digital when overtightened. BTW, overtightening causes the top plate to rattle and that is why Linn added the corner bolt to the top plate.
You may want to have the Ekos looked at as well. The early examples are notorious for having some bearing issues that can definitely affect the sound. Have a dealer give it a once over,