xer987 use the collet that came with the clutch. I recently purchased the K Factory centax clutch for my NTC3 and the clutch is great. I know guys have been saying they would rather a 3 shoe with harder springs, but in my own opion you can adjust a centax clutch more, rather than drilling holes in shoes. Xer987 use 21 t first gear and 27 t second. You will have a ball with the clutch.