There are so many colors that it's possible to start with a close later color that can be tinted to get right. Also, any shop with a mixing bank should have different metallics to get the size right. Main thing is to find a painter who's motivated to get the tint, face (match when viewed straight on) & side cast (viewed at angles) right. That can be an issue on metallics. Some painters are good applicators but don't have an interest or ability to solve problems. Some don't appear to understand light, and some only like slam-bang production paychecks. Generally, a good paint jobber can give you an idea who the most talented painters are, because they should be dealing with their customers on at least a monthly basis.