The MS1-Extra ignition manual shows two alternatives to connect the VR-sensor. Both the opto-in (Ford Edis section) and the VR-in (VR input sensor section) are described. Which one is the best one?

edis is the better option. if the megajolt ever dies on you the car will keep running on the edis at 10deg neg advance which will get you home.

They are both correct. The EDIS one is only for if you are using it though....

I went through the same though process and ended up upgrading the coil drivers in the MS unit to BIP373's which have current limiting trickery built in.

I also spoke to Phil at Extra EFI and he said the only reason you should get problems with on board coil drivers is if you have the dwell set too high and burn them out. He always recommends going for the coil driver route over EDIS, so thats what I did.

Not sure how its going to be long term, but time will tell.

David