First, thanks for the nice words!!
Yea doing the married wing can be a little ticky at the beginning, and even now after a bunch of year it happens that I fail.
The most importen thing for you to do is holding the backpart of the wing VERY tight so it don't follow the tread when you wound it down. When I'm not using a vice i have a much easier way to do it because there is no treadholder in my way, and I can use both thumbs and pointfingers at same time.
So my tip is to skip the treadholder and make this moment without vice using both hands!