I was able to hold the top of the glass and use the handle to lower the window, thereby separating the glass from the channel.
Taped the glass up at the top to get it out of the way. I made the mistake of removing the window regulator and was in a world of **** then, as the glass decided to slip off the tape and had the glass, regulator and division bar to deal with. Looks like you cannot get the glass out with the regulator flopping around like that. As well as that, the side channel near the door lock seems to be in the way. I undid the screws and that allowed some more flex in there. Once I put the regulator back in, I slid the glass down behind it. I found that by winding the regulator all the way to the top, it cleared the glass. I raised the division bar up and was able to remove the glass from the bottom, and then the bar can come out from the bottom and thirdly the regulator. Might not be the right way, but I got there. Those videos were a great help. Thanks for making them.
Saved me a bundle. Local guy here was gonna charge me over $800 to supply and fit. I can now get my own made up and fit myself.
Good luck with it

 

When I took my windows out on my 56 to put in the power regulators I took the glass out the bottom. I took the doors off and laid them flat which made working on them much easier. Taking the glass out of the regulator channel was pretty difficult even once the glass was out of the door.

 

i redid my glass in my 58 biscayne when i broke the glass wasnt that bad i bought the tape heated it up a little and pressed it on a lot of elbow grease ,, ill try to remove out the bottom and see how it goes

thanks