I am curious as to why a imperial 7/8" spanner was used in the video for tightening up the sight window, I'd have thought you would have been all metric by now, especially as you are in Europe, the home of metric. I doubt I have many imperial sizes left in my toolbox these days and I'm sure that's true of most others. Just wondering if the sight window is metric sized or imperial?
Love the kit BTW, extremely well made by the look of it.