Start with a 36-1 tooth triggerwheel as required by the Ford EDIS module. The Trigger wheel must be magnetically conductive to work with a variable reluctance sensor. Materials like mild steel or iron will work while materials like aluminum and stainless steel won't. The trigger wheel in the photos below was cut with a CNC waterjet cutter.
The diameter of the hole is slightly smaller than the diameter of the pulley (small block Chevy, vintage 1969) on which the triggerwheel will mount. Since the stamped steel pulley wasn't exactly round, I chose a diameter about 0.004" smaller than the average diameter. The precision of the waterjet is not as good as one normally associates with a machine tool process, so a little "clean-up" (sanding with a cartridge-roll, normally used for porting cylinder heads) was necessary to bring the inside diameter of the triggerwheel up to the desired dimension.

Here is a close-up view of the "teeth" on the trigger wheel. Notice that the cut is not exactly perpendicular to the plane of the triggerwheel. Close enough for this application though.

1/4" wood dowels were glued to the pulley to space the triggerwheel at approximately the center of the space between the pulley and harmonic damper. The objective was to expand the triggerwheel with heat and allow it to shrink into place as it cools, so the pulley was placed in the freezer several hours before the intallation to shrink it a little.

Later the triggerwheel was placed in a toaster oven and "toasted" on high (~500F) for about 20 minutes to make sure it was plenty hot. In a test to see how much the triggerwheel would grow, a quick measurement showed the inside diameter grew by about 0.010" at 475F.

Then the pulley is removed from the freezer and placed on a piece of styrofoam so it won't warm up too quick. The triggerwheel is then removed from the oven and carefully placed on the pulley and allowed to cool. Notice the "dots" that I punched on both the pulley and the triggerwheel that define the desired alignment. The "other" markings are left-over from the flying magnet arrangement that didn't work as well as I expected. Also notice the hole I drilled opposite the missing tooth to balance the wheel a little better. The volume of the hole is slightly larger than the volume of the missing tooth to compensate for the difference in radial position from the center.

It looks like this when it and the sensor are mounted.

This illustrates the VR sensor position with respect to the missing tooth (assume the crankshaft is at top-dead-center):

The DXF file used to cut this trigger wheel is available here.

I'm very happy with the way it worked out.