I have a boaphile and it's awesome

you may want to call ahead and ask them if it's ok to put a 24" on top of a 36". I called them and asked about putting 24" on top of 48" and his answer to that was no way unless you got a 'coupe' (two door) style of the lower cage so that the center would have enough support to prevent the structure from flexing in the middle.

you may be fine ... but I was glad I checked in my case