Mike,
This is a 300 dpi RGB scan of the Northern Light test image:
The print was on a letter size piece of Arches, using the "dB3, v.2" profile, which has a total delta B from paper base to max. Lab B of about 3.5.
(So, this is not the dB2 profile shown, but that on letter size that one is a bit of a stretch for that target. The black (MK) dithering and paper patterns in the midtones are going to interact with the gradients and leave artifacts.)
Keep in mind that I am targeting Arches full sheets -- 22 x 30 inches. So, on this letter size, unsharpened (cheap) flatbed scan, you'll see a lot more impact on the image from the medium than I would someone looking at a large print. (You'll also see dust on my scanner.)
The image was gray gamma 2.2. So, in printing I applied my conversion curve. This compresses the dark end. While the flatbed didn't separate the bottom row of Keith's 51-steps very well, my spectro does, and the dark end will get a bit darker as the MK cures overnight. That is, there is appropriate separation there even if the scan does not show it.
BTW, I use the dB3 carbon core for what I consider the best Neutral profile, not the dB2 core. But for many images, where someone wants the most archival full sheet Arches print, the dB2 carbon profile can do a very good job.
FWIW
Paul