What kind of printer? What are the six colors? If it's CMYK + Light Cyan and Light Magenta, then you should make a CMYK profile if the printer is driven by a RIP. Only in the case of printer that has a RIP in front of it, AND the printer has 6 distinctive primary colors, AND the RIP is accessing each color individually (i.e. a halftone driver), should you make a CMYK+2 profile. In case there's no apparent RIP, and the driver only understand RGB correctly, then you should make an RGB profile.
You could look for profiles that are shipped with your product, and find out if they're CMYK, multichannel (CMYK+n), or RGB profiles.