I just fired a half dozen pieces to ^6 using the PC20 as a base coat with Palladium, Chun Plum, and Vert Lustre as topcoats on different pieces of Soldate 60 clay. The colors were darker than in their ad, and I'm attributing that to the clay. One thing I did find out was that you do not want to use the PC4 Palladium as a base coat. I put it under the PC20 Blue Rutile as an experiment on a mug. The colors blended but were kind of a muddy dark blue and the glaze ran to the point where I had 5 gross drips at the bottom of the mug. The interesting thing here was that the drips were all the silver color associated with the Palladium telling me that the Palladium as a base coat was NOT the way to go. The glazes held together well with the Blue Rutile as the base coat.
My next attempt using these colors for layering will be on B-mix clay, and I'll be thinning the top coats to see what happens.