I have no Roland inkjet experience, so I should probably just stay out of this one, but I am just curious... for the purpose of this conversation, what exactly does "spot color" even mean? Is this to be printed on your Versacam cmyk printer?
TYhe hairline question sounds like more of a Corel question, but even though I'm not an experienced Corel user either, I remember many threads where people were trying to output Corel files to a plotter & setting lines to "hairline" seemed to be a common way to create cut lines...