Personally I'd use the aquarium, gives them more climbing surface. But most importantly I would suggest it because young cresties need a lot of humidity from what I've heard.
If you want more vertical room with an aquarium you can place it on it's end so that it is more vertical depending on the size/shap of the aquarium. My 20g (high) is on it's end with no problems, and is 24" high that way.
All of the above is just my personal opinion, I am new to cresties myself and therefore could be wrong, but I do a lot of reading around about my pets, but again, just my opinion.
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1.0 Dumeril's Boa
0.0.1 Crested Gecko
...Not that the list will end there, got my sites set on a few others... snakes and other reptiles are highly addictive.