I've always been under the assumption that because of their waste, 3g per frog is preferred, however, because of all the plants in there, I have two in a 3g. It's a large rounded, orb type bowl. It looks like a large beach ball that is cut in half, so it doesn't taper to a smaller diameter at the top of the bowl.
Again, I only feed them live because they've never shown interest in the frog bites, flakes or other prepared foods. I guess I never tried fasting them and then trying other foods, I just feed them what they like. They go insane over true mosquito larvae in the summer! They mostly live on bloodworms and mysis shrimp the rest of the time.
I think if you do plants, you can break the stocking rule, which can be said for most of the smaller fish, IMO. I have two males together, but previously had a female with the male. They produced eggs almost weekly, but ate them almost as fast as they were produced.
Best of luck with them. I find them to be delightfully entertaining.
Sorry, no current pics.