Steve:
When I deal with potmetal, first I sandblast the part to clean it up.
After that I determine how much metal I can remove by sanding without destroying the detail and profile of the part.
For deep pits I will fill them. Sand some more, refill low areas, sand, ......ect. The other pits that are 1/16" deep or less I will use the acid copper to fill.
Your definently going to need acid copper. You may have to plate it 3-4 times with sanding inbetween.
Crystler products are a pain in the rear!!! Thier potmetal always seems to differ in its alloy. I have a 55 Dodge that gave me fits.
But, it can be done with patience.
I think Caswell sells some stuff called solder it that may be used to fill the pits and plate over
48Buick