Main issue with gesture are shadows and background behind your gesture.
You have always to think what is seeing the Spark on its video and how good is the contrast of your hand/arm to background.
Now that the video gesture exists (need to be used before saying byebye to Spark) it is is interesting to use it and see what the Spark see from your gesture and learn from that.
Regarding dronnie / helix and such flight mode, was ok with IOS device. Attempt with previous version of android was a joke. Need to retry now with android. At least with latest version, I didn't has the disconnection during flight with RC.