Some help please with Cartridge choices

The Acos Lustre GST-801 is my favorite Tonearm of mine or any I have experience with. Thanks again to those here who recommended it and helped me find the one I bought.

1. OEM headshell has azimuth adjustability

2. base has easy/smooth/on the fly height adjustment, best I can imagine.

3. magnetics used for tracking force, I measure using a digital scale, the dial is close but not perfect, and it holds it’s setting when I double check everything every few months, or soon after a recent cartridge install.

4. anti-skate is also by magnets, I use visuals of blank LP and refine by ear with 3 guitarist’s LP, not the dial, and like tracking weight, it maintains it’s force when I double check it.

5. internal wires: I forget what they use, it’s original, then 5 Pin Din below the plinth so no ’wire pushback’ to effect anti-skate.

6. very heavy stabilizer/fastener below plinth, 

I had my fun with a 12.5" effective arm, now the JVC Victor UA-7082 is 11-1/8" effective, I like the idea of long/less error, but I prefer the ease/performance of the 9" 801 I mentioned above. I do not think they ever made a long version.

@OP.  I haven't heard the Black so I can't comment on its sound quality. However, at a technical level there are a lot of improvements over the Red. As Hana say, it is not a Red with a diamond cantilever.

But I have two observations. Firstly, in terms of balance of performance, would the additional cost over the Red be better spent on improving the tonearm or phono stage.

Secondly, the Black's output is 0.3mV so it's on the lower end of MC output values. So phono stage matching will also be important,

who has heard a diamond cantilever?

here’s a potential bargain, AT125LC, Open Box, included Azimuth adjustable magnesium headshell

https://www.ebay.com/itm/267441847752?mkevt=1&mkcid=1&mkrid=711-53200-19255-0&campid=5338381866&toolid=10001&customid=7d03d124-b0f0-11f0-86ee-366165326233

what makes it interesting is that after the unused Line Contact stylus wears out, any current VMN stylus will fit it, so you could end up with a boron rod cantilever, you choose from 3 stylus designs

https://www.audio-technica.com/en-eu/support/which-stylus-can-i-use-to-replace-my-discontinued-model

take a look at the list, you can buy a body, no or worn or broken stylus, and simply put a new VMN stylus of your choice on many old designs

AT-VMN45xML (microlinear/nude/boron cantilever)
AT-VMN50xSH (shibata/nude/boron cantilever)
AT-VMN60xSL (special line contact/nude/boron cantilever)

$229. gets new MicroLine on Boron

https://www.audio-technica.com/en-us/cartridges/styli-accessories/a-t-moving-magnet-styli/at-vmn45xml

OEM stylus tracks nominal 1.4g, not sure what a new boron cantilever might want, can anyone guess ________?

and there are a lot of old stock original Line Contact Stylus to be had.

Titanium is involved somehow, I am not sure of the specifics

https://www.vinylengine.com/library/audio-technica/at125.shtml

Another who has, is whom has experienced optimised Cartridge matching between Cart' Output and Phonostage. 

My one experience where I knew all the necessaries were accurately addressed, enabled a Cart' that was very familiar to myself, find a new level of positive impression it could conjure. 

When parting with monies  for a Cart' that can extend to $7K+.

The electronic support for the  Cart', surely needs serious consideration as well. 

This doesn't mean buying into uber expensive electronics, but putting in place the devices that allow the Cart'to be optimised with a downstream circuit.