I currently have a STURDY iron fence on 2 sides of the enclosure, and the 2 existing sides are our yards privacy fence. So far, he cannot get through it. He does climb it, or try anyway. He knows where the gate is, which has 3 strong chains on it, and that's his favorite place to "push". He beds down in the same corner every night (the corner of the 2 wooden fences) and I'm planning to build a shelter over that area.
(At his previous home he had dug a 6 ft burrow under his shelter). I plan to expand the enclosure out another 20' at least. We also have a 30'x40' garden that will get fenced in and used as a second pen for him after harvesting. Of course I intend to let him "clean it out" as well.
I saw your "cinder block wall", is that what that is? I can't imagine him not powering through that!
Understand that your fence needs to provide a visual barrier as well as a physical. Sulcatas often injure themselves trying to walk through chain link, wrought iron or any thing they can see through. 24" would be great, but really 16" will work just fine too. Going 16" high will allow you to use one sheet of plywood for every 24', vs. 16' if you go 24" high.