I wrote about my frustration in being unable to locate manuscripts online, despite having the shelfmarks. Of course I am not the only one to encounter this. A kind correspondent has made me aware of a list of links which helps enormously. Compiled by Albrecht Diem, at the Monastic Manuscript Project, it is here. I shall add it to the sidebar.
I have tested this out with the list of manuscripts of Wilhelm v. Boldensele, in this post. The result was that I located a couple more manuscripts online, which I have linked.
It was still back-breaking work. After a few libraries, I gave up. But it was definitely an improvement.