Choice of Phono Cartridges

Dear @richmos : I think that rigth now you AT TT/tonearm combination is fine to stay with. The tonearm design looks as one of the best tonearm ever made that's the Technics EPA 100MK2, even your AT tonearm comes with the best VTA mechanism ever made where today 20K+ tonearms not even dreams with.
That VTA mechanism was designed by Technics in the very old times of analog audio. So for me stay with and before you change it ( if you do in the future. ) your choice for a better wuality cartridge is spot on.

I agree with the gentleman that recomended Nagaoka cartridges that's like AT or Ortofon manufacturers an " old " way experimented manufacturer too.

You must try this one and I'm sure you can't go wrong with:

https://www.lpgear.com/product/NAGAOKAMP300.html

Due that the AT tonearm designs is a removable headshell design you can match the cartridge with the tonearm for improved quality performance levels.
You can use a different headshells than the stock AT, you can choose for magnesium build material to wood one or even headshells of blended materials. 
With different headshells the kind of sound you will listen is different too.
Even if you don't want to test with other headshells you can improve the sound changing the headshell stock wires for better quality wires.

Anyway, as you posted: "  lot's of information for me to sort through and research .""


Regards and enjoy the MUSIC NOT DISTORTIONS,
R.

I have had both Sumiko cartridges, and currently have both a Hana EL and Ortofon 2M Bronze. IMO, the Hana and Ortofon are superior to the Blue Points.  The 2M Bronze is more dynamic, and has more detail than Hana. The Hana is smoother overall, and is possibly more refined. Like them both. Am also using an AT ART9, and thinking of acquiring a Kiseki Blue or Hana ML. Have 3 TTs in use, and a spare Clearaudio Concept tt with concept MC cartridge. So I’m a bit over stocked on analogue stuff right now.

Nice to read that OP’s tonearm is so good. Easy and finely adjustable VTA is something I didn’t have until last year, so upgrading the cartridge is a good idea I agree.

I think an advanced tip (beyond elliptical) will give better results. And that stylus will last over 2-1/2 times the life of an elliptical.

I did this, I put a new advanced SAS tip made by Jico in my existing Shure V15VxMR body and could not be happier.

That is why I got excited about OP’s option to upgrade his stylus type in his existing AT body

possible to change your elliptical stylus to either a VMN60SLC (special line contact); or a VMN50SH (shibata,).

...................
I got excited learning about the supposed advantages of Moving Iron, MI, until I went thru the specs, finding the separation and channel balance were not very good until you get to the very pricey ones.

Someone said that is not as important as I think, however, I have owned/listened to many a cartridge, for imaging, for balance, in my main and office system, I value both.