Printout a Color Chart and take it from there by tweaking the colors that most closely resemble what you're looking for. Hope this helps.
Randy ensure if you are printing the Roland Color Chart from Versaworks Media Drop Down that you set the queue (A) first with the type of media you are using and that you pick Density Control for your color management option. If this procedure is by-passed your printed results will not look like your chart.
You can also check out this video that walks you through how to use the Roland color system: http://myversacamm.com/video/roland-spot-colors-and-versaworks-sett...