Crib mattress help

Lorena • Sat, Jun 25 • Momma to 3 beautiful babies!🤍🤍🤍

My dad is going to custom make our crib. We need to decide on what mattress we are getting so he can start it, what's a good comfortable mattress? I thought checking our babies r us and target since we went to Wal-Mart and didn't like the ones there.