The filesize will be fine enough, everything in the stage is enabled and working, and the flying version doesn't need anything more. Even if the filesize went hard, I still have some tricks to get some space, so I confirm you that I will make the 'alternative' version of Peach's Castle M64.
By the way, I'm uploading a video showing the roof version of the stage, I'll post it in a few minutes.
So does that mean your also going to be doing the Mario Kart 64 verison as well?
Just curious because you mention it before and all.