Avid Diva II SP or keep my Linn

That is exactly what Linn says not to do.  Try building a mini-shelf on top of the rack.  Use a piece of Corian or whatever and put 3 or 4 cones under the shelf.  I guarantee you'll hear a big difference.  Better or worse?  That's up to you.  The Neuance was sort of a hollow piece of foam, sort of like a surfboard.  It was about 2" thick and very light and rigid.  But I also found that Corian worked well.  Even glass on the Naim Fraim, which is usually a no-no.  

Alternatively, add a Linn Tramp 2 to the table...this helps greatly with minimizing the effect on the table from what it is sitting on. Generally a nice uptick in SQ from this mod.

Did you add a Trampoline? If so what was the improvement?

I have a 1988 LP12. Ekos arm, Cirkus, Lingo 1, Trampoline 2, Lyra Kleos. Maintained it myself all these years with zero problems.

Took it to "Ovature Audio" in Ann Arbor MI. "Tom a longtime Linn setup guy" Drianed the oil, inspected the bearing, replaced with fresh oil, replaced the after market mat with a new felt mat, new Linn cable, new hinges,
said not to use the SOTA clamp any more and installed a new Lyra Kleos. Tuned it in the Linn manner.

Even though I never had a problem; when I got it home, it  "Played the Tune" like it hadn't in years. I put it on the original lightweight Target stand that I bought with it and footfall problems disappeared.

 I have a new Kuzma Stabi S with platter upgrade, power supply upgrade, 12" VTA arm , Dynavector XX2 mkII next to the LP12. Both ply at a high level with subtle differences but one does not outshine the other.

 I am contemplating the Kore and Radikal. Yes, they are spendy. Also considering a Technics GAE modded with a 12" Triplanar arm.

Thinking about my retirement TT but after a tuneup by a Linn master; I would Not give it up. Just keep it in the collection.

Best Wishes 

I added a Tramp 2 last year. It was a nice upgrade and certainly helped minimize the impact of the stand i was utilizing--- a VERY heavy Sound Anchor.
I would recommend the Tramp 2 to any LP12 owner.