The safe combination is a secret, and obviously belongs in secret storage.
In this specific example, if I had trouble remembering whether the first number of the combination was reached via cw or ccw rotations, I'd include that in the secret, e.g. "cw34-12-22-45".
(Some safe combinations require multiple rotations. I unintentionally became the owner of one that is something like "cw3x34-ccw2x12-cw5x22-ccw2x45". I still can't open it actually, but that pattern is what the Internet tells me. :)
Sure, but I will need it at the same time and for the same reason as the combination which does belong in the password manager. To store it separately would be more difficult.
In any event, it's not large. I seem to remember it is only in the low hundreds of kilobytes. But there is occasion for such things.
>I unintentionally became the owner of one that is something like "cw3x34-ccw2x12-cw5x22-ccw2x45"
Mine is similar. I even have the cw/ccw in with the numbers, but that alone never seems to get it for me... sometimes I do need to look at the pdf. I simply don't get enough practice to do it from memory.
I maybe half agree with you about the encrypted overlay filesystem but only in respect to files, not passwords though. I tend not to keep files in KP, if I need a singular encrypted file I'd probably 7zip it (7z format) with a password and encrypt the filenames. The password goes in KP as does the location.
The URL field in KeePass has lots of convenient features [0], but unfortunately they're quite "obscure" and not very discoverable.