Why are you so sure that mags won't support larger gaps? With 
standard Slick 4300 mags, I run my Iridum plugs at .024". The engine 
starts all of the time on the first blade, cold or hot. If I wanted 
to experiment, I would try, and do believe that it would work, 
setting my plugs at .050". If the engine would start in the first 
place, the mags develop more energy as the RPM increases, you could 
be sure that it would keep running.

Has anyone experimented with larger gaps on Iridium plugs or is 
everybody just guessing?

Lorn,

 

If you go to a DENSO site (for example) and read about the benefits of iridium plugs, you will see that one benefit is less resistance to the spark making the jump - better even than platinum.  Your flight regime is not a good example - you fly high (less resistance to arcing), without a hi compression ratio (hi = more resistance to arcing) and at lower power settings.  You will not necessarily see ignition problems with the larger gap because of these conditions.  Regardless of the rpm, mags generally produce no more than 12K Volts whilst EIs are around 40K and CDIs around 60K.  Also, generally, an EI never misses a spark - not true of Slick mags. 

 

Hot starts with a carb do not present any problems - injected engines suffer from vapor locks and premature vaporization from heat induced in the fine lines that run over the top of the engine to each injector.

 

Nothing wrong with your set up - it might not work for folks that have different objectives.  The interesting part is the range extension you probably would achieve with spark advance at the hi altitudes you utilize.  Have you considered trying my LASAR, it is for sale.