There is quite a lot of discussion going on just now on the merits of electronic ignition by Accuspark on 12 volts.
For what it's worth I have just done 3600 miles around Europe with a DK4A on 6volts fitted with a KDA1PP (pos.earth) from Power Spark of Bromsgrove -- cost £45.00 This proved totally reliable and gives excellent starting and smooth running. Doug Castle did a write up on this which is worth reading.
In conjunction I converted to LEDs on all lights (Dynamo Conversions, Lincoln) which allowed me to reduce Dynamo output to around six amps. With all lights on the ammeter still shows a positive reading which enabled us to drive most of the time with lights on, like the bikers -- particularly useful when driving through Europe.
So I would say if you have a car which uses a DK4A and you want to stay on six volts this is worth considering, particularly if you want to combine originality with efficiency.