Tonearm suggestions

I'd take a look at the Audiomods options and the Funk FXR.

Bot have been reviewed by Jason Kennedy.

The RB1000 is much better built than the Audiomods, but is more difficult to do VTA as it requires spacers under the arm base. For your deck I think the RB1000 will give better performance. I've heard both arms and would consider the RB1000 to be more precise.
Why not get an Audio Origami PU7 which seems to be what most Palmer buyers in the UK are using. I'ts Rega mount, and I think you could get a new one for US$2500 ex UK or talk to Hammertone the importer. RR $2900 - surely they can do one for $2500.

All the Origin Live tonearms use the Rega mount. So does the JA Michell and other modded RB250/300/301/303 arms.

I am using a Rega 1000 on my LP12. Works very well; I bought the Moth OEM version as it is $1200 rather than $2000; only lacks the Rega logo. According to UK reviews they are identical otherwise. I am using Pete Wriggle's VTA adjustor which will add another $200 or so to the arm cost. I was using a Graham 2.2 previously and it is a good arm also but I am going with the RB 1000.

I dont agree that the Rega 1000 is much better built than the Audiomods. Perhaps Dover can explain. Everything about the Audiomods that matters is top drawer, from bearings, to micrometer VTA adjustment to VTF accuracy. And its cheaper.

You mike look into Helius Omega also. Excellent arm, unique bearing system and sounds as good or better than my SME IV.