1966 Valiant Signet Convertible Resto

The real problem with metalic / pearl type paints isn't actually the color formulation - that's easy enough to get right, although getting two exact mixes is sometimes difficult enough! The more metalics /pearls in the paint, the harder it is to get a consistent sprayout. Things involved would include temperature, humidity, gun speed and settings, number of coats sprayed, and many other factors. A really big consideration is if the car is going to be assembled and painted or panel painter then assembled. Just the fact that you paint the doors, for example, laying flat on saw horses or upright the way they go on the car - the matalics will lay out in a different manner under these two circumstances and it will be difficult to get a perfect match even if they are painted at the same time as the rest of the car. The more variables you add, the greater chance of not getting a perfecr match in color.
The pearl won't really add to the ammount of shine involved or the work to make it shine. Just about anyone can get shine on a car, but I've always tried to get DEPTH in my paint jobs. When you stand back 10 feet from the side of the car and the reflection of your legs look like they are 1/2 a mile away in the side of the car, then you have depth and distinctness of image. Color sanding and buffing can provide the shine.
By all means, get a pint of each color and do some test panels because that's the only way you'll know if you're going to like the color or not. I was going to put Viper Red on my Vart so I got a pint mixed, sprayed a garden tractor for a buddy of mine, and then decided it would not really suit my taste on my car. I must admit though, my buddy has the sharpest little tractor in the county! :) It doesn't make any difference if the paint is Dupont or PPG, or any other quality name brand, just what your painter is familiar with using. Hope this helps.