I had a chance to put the sail on my iflatable this weekend and I was impressed. The wind was blowing at about 12 with gust up to 20. It sails best in the lower wind speeds. This is a fun boat and very stable, even when the wind gusted to 25 mph, I never felt as if it were going to flip.
I did get water inside the outer skin, the drain plug on one side was not connected to the hole on the outer skin, so I collected about 3 gallons of water. You may want to check the drains on the inflatable to make sure you don't get water inside the outer skin when you go out.
I would think that they would epoxy those in to make sure they don't become disconnected?