Despite my previous comments, one radius holds a unique quality when considered by an observer: the radius orthogonal to the observer's spatial position ), representing his time. Consequently, all radii at 90 degrees and the one at 180 degrees are special relative to that observer.
The radii at 90 degrees would encircle the n-sphere and appear to be at a position where t=0. Unless the hypersphere was sufficiently big for t=0 to occur earlier as a limit of the speed of light due to distance and expansion alone.
This scenario applies to any observer, regardless of their location on the 3D hypersphere. The radii are unique to each observer, reflecting a form of relativity.