If you are using a higher value to C7, the ocsilatrofrequentie will be lower.
If the ocsilatorfrequentie is lower, the load of C6 will be lower.
If C6 have a low loadfrequentie, the sparkintencie will be lower.
This CDI is made for high rpm (>25,000), the commecial CDI you can buy handles till <10,000 rpm.
You can change C3 into a 0.1 uF MKM capacitor opens theT1 gate for X-time.
But.....the time with a MKM will be shorter then when your using a aluminum electrolytic.
The spark will also be shorter, less spark, if the X-time you create is shorter.

But, it's a opensource project so you can change everything you like.
If you can make it better, be my gast [8D]