The Nippon 950GH shafts are discrete lengths both in tapered and parallel. The longest shaft is 38.5 and is designed for the #3 iron. If you put the 38.5 in a #4 iron for example, you would be in effect softening the flex because the head weight is heavier in the 4. Probably about a 1/3 flex softer. There is no tip trimming on either the taper tip or parallel tip.