There’s this little mind trick you can perform on yourself. You can read volumes such as 10455/16099 as 10/16. I’m surprised that 2x5 digits is too much to read. It isn’t to me. I think I’d get annoyed at around 2x7 digit figures, especially if there were no separators. But still, I’d just read the first 2-4 digits and ignore the rest.
I think there should just be a hotkey toggle for the volume number, cycling between ‘rounded’ and ‘exact’, and possibly few others. Maybe drop a text line in the inventory saying “toggle volume display modes with Q” or whatever.