Where the magnet is located is not important. What is important is that the magnet moves past the sensor at 28 degrees BTDC. I kind of work backwards when I set my engines up. I find the most convenient spot to mount the sensor then find where the crank is at 28 degrees BTDC and mount the magnet at that point. Finding a good place to mount the sensor is sometimes more important than where the magnet is located on the hub as you can mount the magnet anywhere on the hub. Hope this makes sense.

Jim