Putting pearl in the clear wasn't the intended way of using it. Dupont or PPG have never said to put pearl in its clear. How ever it gets done quite often. There is no ratio for this reason alone. It takes very little pearl to make a big affect. A half teaspoon is all needed for a qt of clear. If this was mixed with the paint it would be over shadow and the pearl wouldn't bee seen. Being it's is in the clear there is nothing to keep it from shinning through. What your are creating ia a tri coat paint. This is already there to be purchased but it will cost you a lot more their way. This is the poor mans way to to get a tri coat. Two coates is all that is needed with the pearl in the clear, then another coat to finish off. The pearl is grainy and need a coat of clear to seal it off. If you need or want to sand and buff you will need two coats to seal off. Sanding through the clear in to the pearl can lead to blotchy spots. Two coats will help solve this. To much pearl can change the color all to gether. Happy painting.