The roll pin is about 1/16 - 3/64 - get a few sizes at the hardware store and snip them down to length. There isn't any torque to deliver - it just needs to clamp itself on the shaft, down against the stop.
The slots are 180° apart on the shiney replacement reluctors I get at NAPA - the gadget won't care which one you use.
If you get in a bind for info - PM me and I'll help you any way I can.
Steve Metzger Tucson, Arizona