The reason you had to struggle so much is a common mistake when installing these. Never attempt to drop it over the lower pinch weld, you will always have a problem getting it to drop (because of the compound curves) far enough to get the top in. Always center the glass/gasket in the opening, and take advantage of the flexibility of the gasket to rope over the pinch weld. Also these are designed to install dry, no sealant, but I understand the desire to add sealant for insurance.
Thanks for the video. I was wondering,you probably replaced the windshield seal with a new one. Where did you get it ? Also just love the stock colours that you did the truck in. I have a 1978 F250 super cab ,4 wheel drive with the Dana 60 front end.