I found no pics on treats link from cuperteens about putting an e50 cdi onto a derbi piston port or pyramid reed.
This is how I did it, no grinding cases or anything except a lil lengthening on all 3 screw slots.
It works good. Had to flip the high voltage coil over, then time it with no reference point. Wires route out easily.
Found that flywheel woodruff key slot needed to be rotated counter clockwise around from the matching crank key slot by about 140deg. That's for a retarding cdi I'm using. Also had to lap the crank to flywheel taper with coarse grinding compound to make sure it sticks tight.
Thinking of cutting a slot in the crank to accept the new position for the flywheel, cuz then I can set it more precisely and easily with a known position. I think some good masking and a few dremel cutting discs should make it easy af.