I think thats why in the jpeg I linked mpicket used two edis modules driven by the saw output from the ecu. The load of driving the coils was carried by the edis modules.
This also has the advantage of allowing the ignition to operate independantly of the ecu. The edis module with no ECU input will fire the coils with 10deg of advance. The ecu only send the advance information to the edis module.
The EDIS upgrade I am doing does not have an EDIS module, I am driving the coil packs directly fom a signal from the ECU (Similar to using VB291 coil drivers with a megasquirt) I am using an EMS 3 Coil Driver (around $80USD) here is the schematic
Ask the guys at EMS and I am sure they will tell you whether a single coil driver pack can drive six coils or whether you need two packs.