Power window stuck down

The left rear power window is stuck down in my 67 Le Sabre 4 door. I checked the sash, cam, rollers, and stops for pinch points or jams and I tested the motor with both the existing pigtail and a new wire to 12v + so I know that it is bad. I have the Fisher Body Manual which describes the window, regulator, and motor removal. The problem is that to remove the window it needs to be in the up position to remove the lower sash channel screws that hold the window to the channel. With it in the down position, the forward of the two screws is behind the gear.

I have never had to replace a motor before, so I am being cautious as I do not want to damage the window or myself. If I understand it correctly, the regulator and the cams are "sprung" so I need to drill and bolt the sector gear to the back plate before attempting to unbolt any of the components so that I can remove the rollers from the sash channel to raise the window.

I appreciate any guidance on this issue, and thanks in advance.

On the bottom of the glass itself, there should be a track with bolts that attach it to the regulator. If you remove the bolts, the window can be raised to the up position, allowing access to the bolts that hold the regulator in place.