What's a safe guage size for my cartilage piercings?

So I want to get these ball hinge hoops for my 2 cartilage piercings next to eachother. I got them pierced with a regular piercig gun at Piercing Pagoda. I want to use the hoops so it'll be easier to sleep on them. I've had them for 3 months. I want to know what size "guage" hoops I should use that wouldn't be much of a difference from the original earrings. I really don't wanna go back to that pain and I don't want to really GAUGE my ears.