Scott wrote: “Are the Mag plugs top, bottom or mixed?  During the break in phase, some engines will actually be, uh, letting more oil into the combustion chamber.  At shut down this tends to accumulate at the bottom of the cylinder where some plugs are located and may have a tendency to more easily become fouled and even more so on the side where one wing is low when parked.”

I think you are on to something here, Grayhawk.  The Lightspeed fires the top (and presumably cleaner) plugs while the mag fires the (presumably dirtier) bottom plugs, so I may be attributing too much to the electronic ignition.  For reference, the engine has burned 3 quarts of oil in 10 hours since new and seems to be stabilizing on very low oil burn, less than I could detect in two hours of flying.

Fred