Size of water dish?

Reviving for a quick question: how big does the ceramic bowl need to be? Does it HAVE to allow soaking? Also, how much water should it hold

1.2 Normal
1.1 Red-tail
0.1 Albino corn

4 inches wide is more than enough BP rarely soak, the most you will see a BP soak is female during breeding season and even then they still get it done.

Thanks!

1.2 Normal
1.1 Red-tail
0.1 Albino corn