I had good luck wrinkle painting some car parts once, using a rattle can I found at the local parts store. The trick, as explained in the directions on the can, was in painting when the parts and can of paint, and surrounding air were all at the correct temperature. You could paint in temps from 50 to 90 degrees. The temperature controlled how fast the paint dried, and different drying times resulted in differing wrinkle patterns. As I recall, they suggested that 70 degrees was ideal for uniform wrinkles of medium size. I happened to be working in 70 degree weather, and my parts turned out perfectly.
I also experimented with some other parts, and found that the wrinkle pattern changed drastically in differing temps. I don't remember whether warmer or cooler temps resulted in larger or smaller wrinkles, though. It's been a while.