I understand curves are named specific to the printer model, ink and paper. I am using the Canson Baryta Photographique, and see that you supply 2 curves for the Epson 3880:
3800-SEL-CanBarytaPhoto.quad. and 3880-CAR-CANBaryta.quad.
Which should I use for my 3880 running MPS K7 Neutral inks?
The glossy curves we currently have available for download are good custom curves that I’ve made for customers over the years, and are named as the customer labels the paper. The two curves you listed are for the same paper (CAN Baryta Photographique), but one was made for Carbon inks, and the other was made for Selenium inks.
I expect you’ll get better results using the “CAR” curve with Neutral ink that you’re using, because CAR and NU are closets to each other in density (ever so slightly darker than SEL and WN)- though I suggest making a test print with both curves, to determine which you prefer.