If you have 4 ignition outputs you could use some of the coil on plugs off a late model Daihatsu these have built in igniters so no need to run ignition modules, just run each ignition output from ECU directly to each coil.
A bracket would have to be made to suport the coils on an A series.
This way you eliminate additional wiring,modules and plug leads giving you a neat reliable and very effective system, and probably cheaper!!
The dwell setting for these coils is 2.5ms at 12v.
An easy way(but not he neatest)is to braze 4 pins directly on the front of a standard A series crank pully comming out about 10mm past the fan belt so the sensor has plenty of clearance just machine 4 indexed grooves each at 90 deg and sit the pins into these grooves when bronzing into place, file or turn down the pins to the same height.
there is spare boses on the block at the side to mount the sensor bracket.

Use the standard dissy (gutted and locked) with one trigger pin welded to the shaft at the original points cam. then mount a second sensor through the outside of the distributor body for the pickup.
The little bit of play in the cam/distributor gears doesnt effect timing accuracy because the dissy mounted sensor is only so the ecu knows which pin on the crank pully is no one cyl. The pin location on the pully is crittical.
Crank index position will then have to be set up in the ecu to have the pins electronicly lined up with TDC.

For single coil applications running batch fire injection the ditributor sensor is not required but the dissy cap and leads will have to be used. The shaft is still locked.You still get full ignition and fuel control but not individual cyl ign or fuel trim.

Hope this can help a little.