I love the set up. I'm not a leo owner, but will she use all that space? It's really lovely.
The only thing I'd contribute to the sand issue is just that's it a good idea to do a little research on your own on these things. You can contact your local reptile vet and ask them if they've had problems with sand as substrate, read up about the risks, and then apply that knowledge to your own setup. It's always a good idea to find out for yourself.
Sometimes it's hard to tell what information is right or wrong.
One thing, though. It might be a good idea to make one area of the cage sand free - maybe your middle or top layer - and feed the leo there. The biggest risk of impaction is through the sand getting into the food as they eat it. It's extremely hard to prevent if the food dish is anywhere near the sand. You have the perfect tank to have your sand and still keep the food clean - if you can get them to stay on that level. Alternately, you could use a second, smaller cage as a feeding cage and that also helps reduce the possibility of your leo swallowing sand.
