Don't know why I didn't tell you this..

You can lower the height of the cage by putting in a "false" ceiling. You attach 2x4s, furring strips, or whatever works for you around the perimeter of the walls well below the ceiling, then cover that with pegboard or plywood. I would go down by 8 inches at least like everyone else said.

24 inches is fine when using a basking shelf or branches. But for a snake on the ground, lower is better, and IMO 12-16 inches is best for a bigger cage like yours.

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Mark