I've printed on 651 with a Mutoh Falcon 36" using a generic gloss profile or 3651 and it printed very good. I lowered my ink limits by 30% and it printed good. The backing paper is thin and you may have to turn your heaters down. Clean the vinyl with 91% denatured alcohol before you print it, or at least use a swifter to get the dust off.I have several rolls of 651 is why I asked.
Roland said it should be no problem, I just talked with them after posting this.
Time to call Fellers...