Analog Upgrade - Where to start?

I've got a Herron Audio phono stage and line stage preamps, and I love the sound of both of them.... 

Your system is at a high level now - to try and extract even more - you are venturing into the trailing end of the graph and trying things that don't work any better - to your ear - would be quite expensive.

Do what I did - put in money to acquire more records instead.  And maybe some room treatment of it is needed.

(I run a VPI TNT V/SME V/ Koetsu Urushi/ Vendetta SCP-2D)

 I am looking to introduce more dynamic sound, detail (without edge) and musicality.

Put the turntable on a Townshend Platform, with Synergistic PHT Green and Black on the cartridge and ECT on the motor pod. 

Put your speakers on Townshend Podiums, and Synergistic HFT Speaker Kits on the speakers. 

These will absolutely deliver everything you are looking for, in spades. You will be shocked at the improvement, all exactly in the direction you want, at the ability to delve deeper into records than ever with tremendous detail and yet even slightly smoother overall than now. The great increase in musicality will be coming from the Townshend, that will remove a huge layer of resonance coloring the sound that when gone allows all instruments to shine with their natural timbre.  

You have good gear now but frankly will be shocked at how much performance is laying on the table waiting to be released. These will do it. Big time. 

Dear @chilli42 : Yes, 2-3 or more different cartridges is a good alternative to define which ones are the nearest to your MUSIC/sound priorities and this must do it in your room/system and you have to be skillful enough to fine tunning each cartridge in its main parameters: tonearm/cartridge alignment, VTA/SRA, VTF AZ and the like.

Specially in the cartridge/tonearm alignment set up as more accurated as better quality performance.

R.

1. Direct Drive.  
2. Phono Stage based on an LCR network.

1. Direct Drive.  
2. Phono Stage based on an LCR network.

Yeah, this is it!