I used a MOMO shift knob that screws down even lower than stock, for an even shorter throw (not for everyone). I cut down the shaft sleeve to fit. The MOMO knobs have hidden set screws behind a screw-on collar at their base. To provide access to the collar and set-screws I cut the sleeve extra short and placed a compression spring underneath. By pulling down on the sleeve I can unscrew the MOMO base collar and get to the set-screws. Of course, the spring is hidden under the shifter boot. Everything is reversable, except for the shortened sleeve.
Howard
Howard