There in lies the puzzle...
There are certain fundamental elements of a zoetrope that will make this detail somewhat of an 'Easter Egg'. Usually, you need to be able to isolate the images frame by frame. This is done by looking through a slot in the carousel (on a traditional zoetrope).
With the record version you can use a strobe light, or view it through your camera at 'x' shutterspeed. There is even a multifaceted mirror you can place over the center pin, that reflects the image one frame at a time while the record is playing.
So to answer your question... the spacing can relate to speed, but also to detail. I might have to actually use more images, that are CLOSER together, as a result of more frames per second. Less images (spread farther apart) may result in the animation being choppy, or happening too quickly to appreciate.
I am trying to extrapolate, from a 12" record to a 20" hubcap, how many images to use. I will draw out something simple and tape it to the disc to see how/if it works. I might even try and create a slot for isolation on the frame side of the dropouts so it can be seen with or without a strobe/camera.
@OddJob here's an example of the record playing in the video (12" @ 33 1/3rpm)
On further reflection, my points about the animation being choppy or it happening too fast to appreciate, would only apply in one application- if I make the animation go from center to outer edge, centrifugally. If I only do a band around the edge (or a series of parallel bands), then putting the images farther apart would make it repeat faster yet uninterrupted.
