Hello John,
It's all a matter of taste and practical use:
@
www.lamobylette.net in France sells electronic systems.
@ There are specialists, who can rewind HT-coils.
@Some long-distance riders prefer an external coil system, because you can repair those at the side of the road.
On the UK-forum they have written a lot about this issue. So, please make your choice....
Henk van Kessel
www.pantin.nl