Yeah, I used this design pretty much since I have 3 storages (I build them pretty late). And it worked like a charm for me, I switched to a personal creation from me, just to have done it with the additional air defense and the 2 new storages. I also used my own design before I build the third storages.
Oh, and it also extremely depends on your walls, if they're level 6 they're way to low, since a pack of level 5 giants can easily break through.

