I'm printing from LR using Epson Exhibition Canvas Natural Matte, (with Mac OS-X Yosemite, 10.10.5) but the Epson driver won't let me select MK ink, it defaults to PK and is greyed out. I just got off the phone with Epson and they figure its a bug. They suggested I use the Exhibition Canvas Matte media type in the driver for now, which defaults to MK ink, but still use the ECNM ICC profile for accurate colour on the Natural canvas.
Hopefully they'll update the driver shortly.