Well, after reading all your comments I thought let's try it, if I fail I just have to blame you.
So here are some pictures and a new video at the bottom.
Now somehow it got magnetized during the process (tested on a compass) so I'll make a short visit to a watchmaker around the corner.
Well, I dusted off my watchmaker's bench and took a look at what unfinished jobs are lurking in the drawers. One such lurker is the above-discussed AS1171 bumper.
I have never installed an automatic mainspring before. And I don't possess any special tools for auto mainsprings. However, I have heard that such tools do exist. Can I use standard mainspring tools? Anything I should be aware of before I decide to wind it in? Many thanks ahead of time. Cheers all.