1. What is the maximum weight alto stand can handle
An individual alto stand can safely handle 50 lbs. You can actual sit on it and it should take your weight.
2. What size monitor can the alto stand duplex support.
Any monitor that weighs less than 50 lbs and is smaller than 32 inch should fit and be supported by alto stand. Picture below shows a 28 inch monitor. As an example a 27 inch imac weighs 25 lbs and will easily fit on our duplex stand.
3. What is the size of the keyboard tray.
Keyboard tray is 23" X 10", made to fit a small keyboard.