How does the average two stroke ignition curve look?

[Flummo]

I am looking into the possibilities to build a CDI myself, and I have found alot of interesting info. I am planning for a simple device, triggered by either the standard pickup coil, a hall effect sensor or possibly, if I build one for some older bike, by the standard points. Anyway, I have found very little info about how a "ordinary" ignition curve looks at a modern twostroke, I know it first starts early at low rpm and then retards until it reaches the peak torque/hp-area, and after that it adds a bit of advance again. What I want to know is how many degrees advance does it start out with at low rpm? How many degrees does it retard when rpm increases towards peak torque, and how many degrees does it advance after maximum retard?