Pick my next tonearm....PLEASE

All great suggestions and I thank you.  barolobrain (great taste in wines, incidentally!), the AMG retails for $3500 new so I'm not confident getting a used one for my budget.  I'm leaning towards a triplanar 2 I saw on Ebay for around $1500 with the Audiomods 6 as a fall back.  

I run two SOTA Stars, Series III Oaklands.  I have an SME V on one since 1986 and an AMG 9W2 on the other.  I got the AMG used last Sept at the top of your budget range but patience is key for buying used.  Not all arms are going to fit due to the recessed armboard.  For what's readily available and new, I would recommend the Audio Mods 6 with the VTA base.  It fits and is compatible with your deck,.  Further, it can also be adjusted to work with different cart weights and compliances.  Spend the rest of your money on a Cosmos armboard.  Origin Live are nice but I would only get the Encounter or better unless you don't mind having to remove the armboard to adjust the vta.  BTW, if you're never replaced your SOTA springs, the field kit replacement (if you have some diy skills) is the best money you will spend.

Oh, and for less than $1500 you can get a new Audiomods or Trans-Fi Terminator arm.

Both are fine tonearms. You may not need to spend so much though. Look at the Jelco 850S from George Merrill for around $900 with the JAC501 cable.

Origin Live 

Kuzma Stogi (or Stogi Ref if you get real lucky), Helius Omega.

Finding a good tonearm around $1500 (used or new) is almost impossible.

I don't think so, look for:
-Technics EPA-100
-Lustre GST-801 
-Victor UA-7082  

just to name a few very nice tonearms that you can probably find under $1500 

The SME 309 would be just fine. The Grado should perform perfectly in it.

Dear @russellrcncom : You just can't be wrong with the 309 that's a magnesium design that is a self damping material, removable headshell, silver wiinternal wiring and of course the extre quality production levels that SME has and that's second to none.

Regards and enjoy the MUSIC NOT DISTORTIONS,
R.