i only use corkies when i'm fishing bait, and size depends on how clear the water and how large of a hook i'm using.

when going baitless, there are so many better options than corkies(yarn ball, gooey bob, pink worm etc) that i never use them that way any more.

don't tell that to the fall salmon fishermen that swear kings go nuts over a little black corky and black yarn though...