Two thoughts, Chris.
The mixture settings might be way too rich for you at lower rpm. I'm also a bit distrustful of this mistral pinhole return thing.
If the plugs got soaked as she shut down, this might explain the no start.

The other idea is one that has happened to most of us - insufficient volts.  If the engine doesn't turn above a certain rpm and/or the voltage gets too low for the EC2 no injector / coil pulses are sent.

Buly - don't give up. Take the EC2 to Tracy.
John (not upgrading my EC2. No way!).