He looks like he can take a crawler rat. (Rats dont have hopper sizes )

A good measure to go by is compare the width of the rat to the widest part of the snakes body. If they look the same, then the snake can handle one that size every 7 days.

You'll soon get an idea of what he needs and how often just by reading your snake.
Good luck!

Something I noted in your picture, it looked like the cypress was soaking wet. Don't leave them to sit on soaking wet substrate, as that can lead to scale rot if they have to sit on it all the time.

Providing humidity, and keeping substrate wet are two different things. There are safer and cleaner ways of keeping it humid enough for BRB's without forcing them to sit on wet substrate all the time.