I have watched 'miracle' spark plugs come and go over the decades. From the 1960s J.C. Whitney 'Fire Injectors' to multi electrode, surface gap (was good in old-school 2-strokes), rare element metals to every manner of improving the mousetrap. In the late 60s, friends and I added all of the J.C.Whitney claims for their catalog gizmos and doo-dads when added to an air-cooled VW bug. We ended up with something like 400HP. For less than $200. Then we wondered where skepticism comes from...
The Iridium plug with narrow ground electrode and fine center wire strikes me as being as good as we will get using electrical discharge technology. Better wires help, but better coils will probably do more than that. All three in combination would be the best, as the OEM components are always tilting toward the cost accountants.
With the V11, we are talking early aviation combustion chamber tech. Air cooling. Wide valve angle. Heavily domed pistons. Limited compression ratios - especially with what passes for gasoline/petrol these days. Dual plugs help with such a large chamber, but it is the basic design that is the primary limiting factor.