Try this Don--
One recommendation which I might add to ideas are to place a strong, small diameter string in the rubber part of the window seal prior to your helper pushing hard against the glass. Then, once the glass is being pushed hard from the inside, gently pull the string (from the outside) around the circumference of the seal, allowing the rubber seal to flip onto the body metal. I used this method when installing the rear window, and I did the installation by myself in about an hour. This process may allow you to eliminate the plastic or metal hook he mentions.