You have to place the magnet exact TDC of the engine.
The program calculate backwards from TDC to BTDC.

@Charlie, I was making a joke.....I can't be dissapointed to anyone who build the CDI !
My problem, I can't write like I think becourse English isn't my first language.

I can see Brett help me to translate babelfish to real english, thx

@Brett, I hope this is the problem I understand you have ?
The diameter of the flywheel doesn't matter.
The distance between every degrees is of every flywheel the same, also the time !
If you pick a point near the centre or 20cm from the centre, it takes the same time to spin around.