As for stator rewinding. Been there, done that lol. This is one of my prototypes. The ignition side is very hot. I've managed to stuff so much wire into it, that the coil started rubbing the inside of the flywheel. 
If your OEM CDI is old and worn out, that can easily contribute to weak spark.
As for a price, I was thinking $200 would be fair.
I've also started designing a CDI with some adjustments. I Plan on it being an OEM replacement with some switches that can be flipped to adjust the ignition timing curve. It'll have marks set up to match the oem settings, but allow for some room to play.
I just wanna go fast. If your not first, your last!!
Reproducing the Tecate CDI. Contact me if you need one. I'm most accessible on FaceBook. You can find me on the 1984-1987 Kawasaki Tecate KXT250 Group.