Suggestions For Analog Upgrade - Tonearm or Phono Stage?

tough question , always more difficult with a well sorted system as yours is. The Dyna you have punches well above $. i would keep it and wear it out. Kuzma is safe bet, 2 bad the newer Triplaner do not fit SOTA.
best to you
Jim

Listening to and using a tonearm are the final steps in evaluating an arm if you get the chance. Tonearms are straight forward mechanical devices. Most of the elements of a tonearm's design are clearly visible. 
My own approach involves a set of criteria which I think are essential in achieving the best performance. Once those criteria are met it becomes necessary to evaluate criteria which are not so obvious like the resonance characteristics of the arm tube, ease of use and quality of construction. Using and listening are the best ways to do this but unfortunately, many of us to not get the opportunity and have to go by the opinion of others.

With arms that are being modified by secondary parties you can not be sure of what you are getting. SME is a very technically sophisticated company. I doubt anyone is going to make a significant improvement in performance with one of their arms and is more likely to do the opposite. Why would I buy an arm that needs to be improved? There is nothing I can do to a Schroder CB to make it perform better. 

Hi sbank  'Spencer' you have been very fortunate to have participated within a group with such a wide range of systems and experience.
I also fully understand how it can be to be insular when it comes to experiencing HiFi and lose a broad spectrum on how systems can sound and compare to ones own set up. The social interactive side is my most enjoyed part of my HiFi Enthusiasm and I do local group and planned for journey's to meet with like minded friends.

As a direct comparison it is difficult to offer a description as it is a long time since all Tonearms have been compared, one description that might help is that a Audiomods and SME IV have a similarity it their presentation.
When a Tonearm Design is used that can offer a unconstrained delivery that is differing from the above two designs it will show itself with quite a noticeable separation.
I loaned the SME IV to a friend during 2020 and they used this as a Benchmark against other Tonearms being trialled, in the end the a
12" Glanz Model was selected to be used.

I thought my go to Tonearm in use for the past few years was quite separated to the usual Tonearm Designs I am familiar with, it certainly has a standout presentation, that is without constraint, with a musicality  and airiness to the delivery, capable of immense detail retrieval,
which are the traits that won me over and this has been my end game Tonearm in my mind.
The recent demonstration of the New Design Tonearm has made me rethink the end game thought and I am eagerly awaiting the next opportunity to listen to it.
These type of assessments are subjective and it is difficult to explain the properties of the design that contribute to making such a positive impression.
How this Tonearm Design would separate itself from my owned Audiomods or SME IV is something that can put on the agenda for the future. How the test parameters are to be set up to be equal will be the challenge, I'm sure something can be created to allow for each to offer a reasonably accurate comparison.

Good Luck with your Socialising with Like Minded HiFi Friends in the Austin Texas Area, Blue Grass and Blue Steak evenings are sounding quite inviting.