Sometimes... the prop hub limits you from going down to the spinner size you desire for appearance. In those cases, you can find that the shaped prop nuts by DuBro and others will work (great for apprxoimating the rounded hub on a Corsair....)

Or maybe the shaped nut is too small and the smallest spinner that is safe to use on the prop is too large for the desired appearance. We usually fudge with an oversize one when that happens. Some people will build up the prop hub and CARVE a custom spinner in this case...