Hallo Vladimer and all,
Like Vic says, after the first "library" or reference scan, you would probably then be selective about future hi-res scans, so a 1,6m roll would be a pain in the a%#$ when you only wanted a couple of negs at a time ?
I am still using a huge box of neg sleeves I bought three years ago, but (and the point of this post) it seems to me over the years that the practical and commercial standard is six-frames per strip, not four, so that would be the preferred size to use for any storage I suppose. My K-M neg holders for scanning are certainly all six-frame, as well as all the archival products I have ever seen.
I would guess that the high-street outlets cut in fours, so that the film will go in the same envelope as a 6x4 print.
With the great quality of your pics, looking after the negs and keeping them flat is a very good idea 🙂