[Pi Is Exactly 3]

I'm thinking that it's going to be difficult for teams to be able to cap 4 at a time. They'd need a pretty strong arm to be able to lift a 36 lbs in tetras (which is about 28% of your robot's weight) AND since that's being lifted away from the robot, that's going to be a lot of torque on the manipulator. Then you need to worry about weight distribution even if it can carry the torque load. Certainly this is possible, but difficult. I will be impressed to see 4 stacked at a time.