If the Pantone color doesn't have to be 100% dead on, maybe consider using one of the RFU silicone inks from Nazdar. We have had really great results with them (3500 series) on 100% poly. I have only used the RFU colors, but it looks like they do have a PC mixing system for it. It would be killer if nazdar would offer a pantone matching service for that system. The Si ink system is pretty spendy, and for guys like me that only use it on special occasions I can't justify dropping the cash for the entire PC system yet. It would be nice to be able to order a quart here or there for those rare times when you need a dead on match.