The problem that you would most likely have is that the 36mm gearmotor (or the globe) will not support the arm when not powered, the arm would fall down of it's own weight. We have a similar design, and purchased a gas spring from McMaster-Carr, which seems to do a decent job of supporting the weight of the arm. We are using a BB 125:1 gearmotor, and the arm weighs about 5 lbs total, and is about 5 ft long at it's longest. We have an 8:1 chain reduction at the arm pivot.
You might be able to use one or two of the window motors, with quite a bit of chain reduction, and have it support the arm without backdriving the motor, but look carefully at the torque it will take to lift the arm, and try to pick a motor or support the arm with some type of spring so the motor is only loaded to about 1/4 of it's stall torque (as found in the
Guidelines, Tips, and Good Practices manual)