The VF500 stator is thickest, 20mm measured at the core, not at the windings. The Ninja stator is the thinnest at 16mm. Some where I have a list of all the compatible stators with their thicknesses. Darned if I can find it now. If I remember right, the Ninja is the thinnest and all others are thicker (the Quadrunner may have been the same as the Ninja). The VS800 stator I tested had the exact same dimensions as all the VF500 stators I've checked.
When I was running a banshee bracket (glued straight to the motor) and VF500 stator, the spacing was spot on with no room for an adapter plate. Had I known at the time that the Ninja stators were thinner, I probably would have just made an adapter plate and run the thinner stator rather than cast up a bracket to accommodate the thicker ones.