Stan, agreed on every point, except the wasted spark/COP will best a single coil for FAT spark, especially near redline.
My ultimate (possible for me) aircooled engine would be twin plug, EFI, with coil-near-plug sequential injection AND ignition, and be 2276cc(82 x 94) with Nickies or JPM cylinders and JE forged pistons at 11:1, with an 86B and 1.5 rockers. Still NA, no turbo. And of course valve seals, piston squirters, and dry sump, natch, because @Stan Galat. Pretty much what I have with 4mm more stroke and more compression and MORE...
With respect to sequential, it requires a cam position sensor. If building from scratch with a new case, It has to be possible to put a wheel/sensor on the cam gear.
With a little time and patience for setup, I'm sure I could build a STRONG jig of steel that would enable positioning a head for that second plug drilling/milling/tapping. Simply clamp the head and clamp the jig to the mill table.