Very interesting tests indeed. I have a few more questions:
-I don't know what kind of insert SUPs use, can you link to some pics or explanation?
-In your test, you had an Aero with this mastbox extension, and you STILL couldn't make the smallest sail work, is that correct? So what do you think, could Prokids Go be made to work with 1m rigs? I ask because I can't try any boards before ordering.
-In your (vast) teaching experience, what is the age (or weight) when you can effectively teach kids on all points of sail?