VPI TNT HRX table - what tonearms?

I believe, with the TNT HRX, you are stuck with the VPI tone arms because they are completely top-mounted. The TNT HRX has a very thick plinth with no provision for an arm board as such. Unless VPI has a version of the HRX with and arm board cut-away that I don't know about, no other tone arm will work except VPI's own 'arms on the HRX.

Now the TNT-6 in the non-HR version, on the other hand, DOES have an arm-board. And in that case, I would try the SME iV first, then the Graham.

What is/are your cartridge(s) and what is your phono stage or phono section?

I suggest you try the JMW that comes with the table. If you like it, you could save a lot of work.

The HRX does not come with interchangeable arm boards. The arm is mounted in a hole drilled through the three-layer (plastic, steel, plastic) plinth. (I understand that the proper drilling of this hole is a serious machining job.) The JMW arm is physically larger than the Graham 2.2 and most other arms (probably including your SME IV). In order to use another arm, you need to have the hole drilled in a different place, and that place has to be precisely located to fit your arm. Your arm manufacturer needs to communicate with VPI for this. With the Graham 2.2, a little platform of a particular height is needed as well.

When I bought my HRX, I ordered it without the JMW, and I requested that it be drilled for a Graham 2.2, which I now have mounted on the HRX. As a result, I can assure you that VPI has been sent the specs for locating the hole for the Graham 2.2. I can attest that the HRX sounds very good with the Graham. Of course, I have not been able to compare the sound with the JMW or the SME arms. I explained my rationale for choosing the Graham over the JMW in a previous thread (try an Audiogon search for HRX). I have a Graham Phantom on order, with an understanding that it will fit into the same hole as the 2.2. I'll save the dustcover saga for another occasion.

Good luck.

Dear Suttlaw: With your Koetsu cartridge the SME IV will be the best. BTW, I think that you can really do a great improvement in your analog system if you choose to change your cartridge for a better one.
Regards and enjoy the music.
Raul.