Mike,
I have and 8400 and print almost exclusively on Epson Exhibition gloss canvas which I then gallery wrap on heavy duty stretcher bars and spray with Glamour II by BC. I had to have a custom profile made since, of course, epson doesn't provide profiles for printers other than their own printers.
I used to print with the same canvas on a Epson 7600 with the canned profiles from epson. I am very satisfied with the resulting prints on the 8400. The colors are deep and rich. If color accuracy is an absolute requirement for you then you may have to play with a profile or two to dial it in exactly.