Anyone know how to get the pop out windows to stay open?

Yes, but no guarantees. The hole in the glass where it attaches to the window is quite large. Loosen the hinge at that point and push it as far forward as possible while re-tightening the screw (window closed). That will put tension on the hinge when it's in the open position. You may have to experiment. Worked for me when I was rebuilding the windows.