I'm facing the same thing, my Mutoh needs a new head and prints look good as long as I don't have to print a solid black which shows banding. I'm thinking of just subbing out my prints since I've been doing more Routed and Dimensional
signs anyway and I'd rather invest in a larger CNC. Print shops are like coffee stands around here... there's one on every corner practically.
The communication language on the plotter has to be switched from HPGL(communicates with RIP program) to GPGL (communicates with Cutting Master) to get that to work.
I used to print some decals on my Mutoh for a guy that he cut on his Mimaki CG-130. I just printed the PDF file he sent me with the registration marks already there which he created in Fine Cut (Mimaki's cutting program... like Cutting Master is for Graphtec). I just printed registration marks along with the graphic and of course left enough room around for the rollers and top and bottom.
I can't remember how to switch from HPGL to GPGL... I'll need to read the manual...ha ha it's been a while.
Send some sample files with the registration marks generated in Cutting Master to the company that prints for you. Just have them print on cheap vinyl and give it a shot. I need to learn how to dial this all in myself as well. Maybe we can PM each other and get it figured out. I know it can be done.
Good luck!