So I just installed an adjustable brass nut. As I mentioned, I got it not because I think brass (or adjustability) are superior qualities, but because I want the ability to switch between EADG and BEAD tunings. I don't know if there would be any issues running EADG in a nut filed for the larger BEAD string gauges (does anyone know?) but this way I can avoid that scenario either way.
So far so good, but I did run into an issue that I'll need to address. I think to save on machining costs, there are only two sizes of slots cut in the adjustment "screws" or whatever you want to call them, rather than 4 different sizes for 4 different string gauges. It uses two of the large size grooves for E and A, and two of the small size grooves for D and G. I'm running kind of beefy round wounds, and the D string (or A string when I'm in BEAD) tends to pop out of the nut slot. A minute or two with a file should fix it, but it highlights a potential issue with the design if there's side-to-side tension on the strings at the nut due to the headstock shape and tuner locations.