Welcome to the B9 sphere Jesse
Usually when I assemble my posts, I try to cross-reference pages to make sure I'm not mis-interpreting things. Like you, I did a double-take when the B9R-2-Black product page mentioned the "Pigmented for 70-120". In fact, I had been so excited at the announcement of Black resin, that I had glossed over its actual specs and presumed it went wayyyyy lower than 25 microns. When it came time to re-slice my STL mesh for the newer v1.2 printer, the 1.80 software's listing for Black Material suggested the lowest I can go is 30 micron slices. So the way Mike Joyce phrased the product, I'm presuming is following some norm established elsewhere. All I know is Black can hit 30 microns in thickness (thinness?) with no adverse effects. I believe the software allows overriding the suggestions where you can slice and print thinner, but some hints from other posts might indicate the control of light bleed would provide no gains.
I've set the projector distance on my v1.2 to the 30 micron X-Y setting and being a fine-detail snob, will be highly reluctant to change that. IOW, regardless of what resin I chose down the road, my prints will always be 30 microns in the X-Y direction for each projected layer.
In the end, I sliced and printed 30 micron layers for the Black resin print. Nothing mixed. Straight outta the jug.
In the Cherry resin print, the B9 software indicated it can do 25 microns, so that's what the STL got re-sliced at. 30 microns X-Y (locked), and 25 micron Z slices.
As to relying on images. The model started as a Sculptris sculpt. By it's origins, it has organic undulations on the surface - NOT topologically flat. There are far too many factors to list that drastically changes what I shoot, what you see, what you get. I'll try to touch on a few...
If we truly want to take everything into account here, it should be noted that Black Resin Dragon Print was the SECOND EVER object to be printed on the newly assembled machine. Print #1 was the calibration peg forest (shown above). As automobile engines have a break-in period, I would posit that the new parts on a B9 might need a few prints to harmonize with each other. By the time Red Dragon was printed, the machine had over 20 prints under it's belt.
Black resin's nature of the thresholds where it absorbs & reflects light causes it to look more contrasty. A small rotational shift causes an undulation to either be exacerbated or disappear. This also applies to the "legobricking" effect.
By now, I've seen the results of enough B9 castings to know that despite what I see from the photographs, the grow layer lines get mitigated considerably. Run the gold or silver casting under a fine-polish buffing wheel and you'd be lucky to see any grow lines survive the process.
However smooth the Cherry photo might appear, it does contain some topological fidelity that the lighting doesn't show. IOW, Cherry photos turn out overly smooth and doesn't always convey the sculpted undulations that are actually there.
In the end, the B9 Creator and its resins produce detail that requires some serious heavy-duty magnification to both appreciate and pick apart. Contrast this with FDM prints where the un-aided naked eye easily picks out the layer lines.
If the underlying question is whether Black or Cherry provides the tremendously greater amount of detail, my answer after weighing all the factors into play is that both are too close to make a summary judgment. Thankfully, it's not like you are forced to make a set-in-stone Sophie's Choice. Once the initial calibrations are done, the B9 Printer and Software make bouncing back and forth between Black and Cherry resins a breeze. Get an additional vat & build table for the 2nd resin and try both. For miniature figures, I think you'll come to the same conclusion that the in-person comparison is too close. The only other deciding factors will then be whether you favor castability over speed. Cherry provides the former. Black will complete the print in roughly 20% faster time. In a production environment where the resin print itself is the 'product', Black resin might allow at least one more build platform's worth of prints in a given workday AND because of the shorter per-layer exposure, stretch out the interval of changing the PDMS.
1129 layers of the Dragon Print sliced at 30 microns takes:
4 hours 27 minutes to print in Cherry
4 hours 16 minutes to print in 1:1 Red/Cherry mix
3 hours 40 minutes to print in Black