Personally I'd go for 3 hides: one floor cool side, one floor warm side & one "sky hide"- I have no experience with Morelia, but my rat snakes are all fairly arboreal, & they happily use all 3 at different times. So if you have the space (& you do) I'd say "the more options, the merrier". Options encourage not only the proper temperatures, but movement & exploration, from which I believe they benefit. Same goes for a humid hide where appropriate- I've never seen a snake yet that didn't find moist sphagnum moss to be a treat- it's also about textures & feeling snug. As far as a second floor hide, you don't have to purchase something identical- just as long as you provide something that gives cover & feels similarly "secure" to a snake.