Its simple read the fine print
PN 125 is a Syncro Spark Single Cylinder igitions module for use with a 1/4x32 spark plug. For use in something like a Saito 180.
For a Weedie you would want PN 26 or 126 (same but with syncro). These are ONLY a complete ignition system.
PN 98 is a complete ignition conversion kit. ( missing a comma in the web site) it is an ignition system AND a prop hub, nut, washer, magnet, sensor and bracket.
You would need PN 98 with a Syncro Spark upgrade and a short shaft adapter ($5).Your Wacker flywheel adapter is not of any use here.
If you don't have a NEED for SPEED then you can retard the timing so that the power is the same as the mag you are running, that way you won't need the Syncro Spark. The Syncro DOES NOT ADD any power to a properly set up engine.[X(]