Are you feeding this through the main feed or fine art (like back or front feed)? Since Canson Photographique Baryta is thicker than actual gloss paper, choosing the Exhibition Fiber media type on printer and print settings, it may have you feed from front or back (if it offers the options). This is because the thickness may be hard to work with on the main feed in the bending process where the other 2 feeds are either completely straight (front) or the back has a slight curve when feeding.
I've personally printed on media like this on the P800 and sometimes it went through the manual feed (if selecting Luster media type since it's a soft gloss paper), of the Fiber option (closely matched the weight) so the printer knows how much ink to lay down properly, but fed through the front or back without head strikes. This may be different per user, but just make sure you select the best media type (if it's not Epson paper) so it can feed it properly and print. I've barely messed with the platen gap spacing unless it was for posterboard.
The OS and software to print from won't have any affect on printing unless the OS is too old where the drivers aren't available for the printer. It's more of the settings being selected.
