I run the opposite: I have the EI / auto plugs on the bottom and the Bendix mag / Aircraft plugs on the top. The thinking is that the EI sends a 70K volt spark and the Bendix, on a good day, sends a 19K volt spark (hence the different gaps in the plugs).  Since the bottom plugs are the most likely to foul I put the hot sparkers on the bottom. That coupled with aggressive leaning for cruise and taxi have worked great for 700 hrs or so.

Ion

0-320 Long EZ 1320 hrs.
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I'm running electronic ignition with auto plugs on top and magneto with aviation plugs on the bottom. The aviation plugs are REM38S. Recently, two of the bottom plugs have gone bad with one measuring 9k Ohms and the other 130k. (Normally, they should be in the 1.2k region. ) so, I'm trying to decide whether to change all to REM38E or just replace the 2 bad ones with REM38E. At $80 for each REM38S, I'm reluctant to continue with them, even if they are superior for resisting fouling.  Suggestions?
--Jose