I had trouble getting all of the windows back on our '72
Sovereign after taking them off to clean and install new gaskets. Some of them you need to hold in the open position as far as they would go to slide back into the hinge, while others worked at about a 45 degree angle above horizontal. If you cut part of the hinge off, then the window will be able to slide forward and backward in the hinge. There are stops in the frame that you need to center the hinge in between. Then, for most of our windows, holding them at the 45 degree angle I mentioned, plus pushing up on the center and then the outside edges of the hinge popped them back into place. It was a two person operation, with one of us holding the window, and the other one guiding and then pushing the hinge upwards back into place.
Chris