Colder dough will leopard more but it will be harder to open. I'd suggest 2 hours of tempering the balls at room temp before making pizza.
I'm sure there is but there is some disagreement on what it is. However, there isn't any disagreement I know of cold dough leopards more. It doesn't have to be cold all the way through either. Just 20-30 minutes in the freezer can make a noticeable difference.
To be clear, I'm not suggesting this. I don't think it's a good thing to do if pizza quality is your goal. If you just want stark leoparding because it looks good, that one thing. If you want great pizza you should be doing things to make great pizza not stark leoparding. In my experience, the best Neapolitan pizzas don't have a lot of leoparding, and the leoparding they have is not the high contrast type - rather is a much more gentle spotting on even browning.
To be clear, I'm not suggesting this. I don't think it's a good thing to do if pizza quality is your goal. If you just want stark leoparding because it looks good, that one thing. If you want great pizza you should be doing things to make great pizza not stark leoparding. In my experience, the best Neapolitan pizzas don't have a lot of leoparding, and the leoparding they have is not the high contrast type - rather is a much more gentle spotting on even browning.