Thanks for all the hints!
I wasn’t aware that I could use "series:true"—this is the solution I now use, reducing the catalog from 9.3 to 7.1 MB (I must have too many series!).
So my actual search
before creating a series catalog now looks like
Code:
series:true and search:"=Exclude books tagged no-transfer"
because I want to exclude books that I don’t usually copy over to the device. (Those have a tag "no-transfer" and are usually text books, manuals and test files.)