I'm still gathering the currage to put a dremel inside the cylinder I have measured all angles, and dimmensions and all is like you said. The most critical part is transfer ports size and timing. Together with that the exhaust port timing should be extended (this is easy job).

The engine is already cut for either glow or electronic ignition. I made a prop hub the way I can easy put 2 magnets here. I would use Vlach ignition that requires 2 magnets, but is cheapper than CH. Vlach II has also nice feature that stops advancing timing when battery voltage is low. This way the engine still runs about 4000-5000 rpm for safe landing but you know that something is going on. Also with lower rpm ignition takes less current so the baterry even at low level last long enough for stress-free landing.

But before I start with that I need to stop the shaking of my hands every time I think about dremelling

RysiuM