A Schon shaft will only go onto a Schon pin.
Any other 5/16 x 14 shaft will go onto a Schon butt as long as pilot is not too long.
Never seen one too long for a Schon but thought is should mention it just as well.
Now my opinion....
Put only a Schon piloted shaft onto a Schon butt.
A 5/16 x 14 piloted shaft or flat faced shaft just does not feel the same.