When we did our certification( the entire thing) on AC last year, we would usually spend 2 or 3 hours of the morning in class( a thatched hut) and discuss PADI manual and video, then break for lunch and then practice our skills off of the Ramon's dock or go out to Hol Chan. After our instructor felt like we all knew what we were doing, we would head out to dive in the afternoon and we would work on our skills at the dive site.
We liked it this way. We did study a little bit in the evenings, but it wasn't bad at all. It took us 3 or 4 full days.