I'm thinking each individual boom arm can carry multiple robots. So you can service the entire radius faster.

As for robots with wheels, I was thinking about doing away with the gantries all together. Just let the robots move through the area themselves.

I understand better your gesture recognition method. It might make RSIs go away if the robot picked what the human pointed at. =)

And, yes, except in very few cases, greenhouses don't make sense. Someday...