I believe that the degree of wrinkle for the I.Bronze Wrinkle Finish depends on the drying temperature. I got either small or large wrinkles when doing various oven drying temperatures on a few trade stimulators years ago. Perhaps, it would work the same for the Hammertone. You would have to experiment. Drying inside versus in the sun(which would be almost instantly dry here in AZ )could make a difference.
BTW, I believe that WD-40 is essentially Kerosene with a couple stabilizers added. Some Pinball guys call it "liquid death" because it gums up moving parts when it dries up.
Hope this helps.