The more I watch those special stages, the more I think there might be room for improvement. I'm probably thinking about it too much, but maybe not.
For example, at the end of special stage 2, the last two sets of 12 blue spheres occur right next to each other. Pardon my crappy paint skills here:
This has probably been tested, and I haven't tested it myself, but on paper it looks faster. My understanding of the special stages is that they are done to get as few rings as possible, mainly to reduce the length of the score count-up at the end of the stage, but surely it would be faster to accept a few rings in order to travel a shorter distance overall? Besides, there wont be that much difference between the speed of a 5 ring count-up and a 2 ring count-up, for example.
I'm probably just splitting hairs, but I still cant shake the notion that the special stages don't all follow the most optimal route and there is room for improvement. With it being a somewhat 3D area it is understandably harder to plan for, but not impossible.