I honestly have not watched the videos when attempting my first rebuild. Only the tutorial with some pics. I just laid everything out on a nice white cloth and didnt lose a thing.
I have not found the need to reshim any of the za50's I rebuilt but nothing was too far gone in them to cause excessive wear in the tranny. And if the mileage is less than 3k you should be fine with the original shims. I believe it is at 3k they advise checking out the shims but I might be a little off on that. The manual I have is only for an e50 but that is when they advise doing transmission work.
Ken and Graham are really more the gurus of this realm so definitely consider their words carefully.