We’ve looked at a few of the “downcut” V cutters under a microscope, and they didn’t appear to be downcutting. So, we sent them to them of our cutter vendors for inspection, and they also said there’s no real down-cutting in the way they’re ground.
Personally, I’d use a very sharp carbide cutter, like the Kyocera you linked to, or one of our “Ocho” V-cutters.