I asked the question elsewhere and got all of the same information with one key difference.
Damage, the popular option for tightarses like me is to run 8 coils in wasted spark configuration and configure to sync once per 2 revolutions which still allows sequential ignition trimming with wasted spark when combining the cam phasing (cam sync) with my crank trigger.
The GM Gen4 coils are proven to 1200rwhp in wasted spark (keeping dwell under 5ms so they don't prematurely fire!). To prove a point, a guy with a shop in NSW ran one single LS coil on a blown big block and it made 1000hp at the engine. Nuts!
I can ditch the MSD CDI which I'm happy to do as I'm a bit suss about MSD Digital 6&7 quality.
The Mercury Marine IGN-1A smart coils are an even better product (and Damage I'm sure you know all about this brand
) with the built in ignitors, but they're a bit more exxy than the pov LS coils.
The thing I need to do is power up my ECU to remind myself what outputs I had previously configured. If I use 4 of the 6 for ignition, I think I only have/need elec fans and the second fuel pump that comes on above a preset boost pressure. If there's anything else I've forgotten, then I'll need to open my wallet and get the ignition expander...
Thanks for your comments; it's fun getting my head back into EFI conversations after only stuffing around with Holleys for the last few years.