I'm back!
   Um the EDIS 4 is wasted spark firing two plugs at the same time with one
coil every 180 degrees.
Sounds ideal from the rotary, but not so. The coil will be over loaded
because both plugs are under high pressure. The plug on a 4cyl, that is in
the exhaust stroke, does not require as much energy to fire as the power
stroke becuase of the lower pressure on the exhaust stroke. If you could
make the EDIS work with a coil per plug then it would be a good solution.
The Megasquirt site has good info on this.
   Two EDIS4 systems might be worth doing. They are cheap enough and it
would add redundancy.
   Or on EDIS with four LS1 coils.
"http://www.megamanual.com/ms2/EDIS.htm"
"http://www.megamanual.com/seq/coils.htm#ls1"