I did this when attempting to install reinforcement for my deck on the underside. Most of the time most of the strips of wet cloth would fall down. It was the job from hell, and the results showed it. I had wedges, and support twigs, and wax paper, and ,and and... All trying to get the cloth that wanted to fall down so badly to stay up.

I don't know why it never occurred to me to turn my boat over and let gravity work for me instead of against me. I would strongly encourage you to not repeat my mistake if at all possible.