That size cage would work well for Woma's or any of the other meter to 2 meter length Boa's or Python's.

I will urge you to fall in love with an animal via research and build an enclosure for that then to try and find one to fit the enclosure you have.

My logic is that if you develop a passion for an animal it will thrive more so than one that just fits. Particularly when combining your hobby with a youth. Kids now day's have a attention span of gnat, aside from texting...

I would defiantly take their passion into consideration, within reason.
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Jeremy Payne