Your going to think this is crazy, but we used to use paint mixing sticks and loosely screw them to the wood frames. when you would pick the screen up the weight of them would let one end fall and act as a prop if you don't screw it int he middle of the paint stick. With some easy engineering you could make a mount that would attach to the side or top of a metal frame.
With one hand you can gently lift the screen and swing the paint stick back up.