Good bowl size

So I've fallen in love with the idea of using ceramic baking dishes for water bowls. I can get them in sets and put them through the dishwasher and there will be enough of them that i can have extra while the dirty ones are being put through the wash. Do you think 6" wide 2" tall dishes might be big enough for adults or should I look for something bigger?

I use ceramic dog food crocs about that size. They work well for me

That's exactly what I use for my hatchlings/juveniles. My adults however get larger ones because their tubs are larger, and I need more humidity. I'm guessing you'll need larger ones for the same reason. Plus those little ceramic dishes get knocked over by the adults, they just aren't heavy enough. I use $1 dog bowls from the dollar store, they are plastic and easy to clean. Just make sure you get a style that can't tip. The dog bowls I use are the kind the expand towards the bottom. You can find the exact same bowl at Walmart for just over a dollar. It's black/blue/silver with dog bones on it. It works perfectly for me.