In one of my wild variety of jobs, I used to work as a curator, for a photographer, so am very familiar with the difficulty - and importance - of weeding out the less than perfect photos. In my
experience, it was most effectively & efficiently accomplished as part of a system of categorization. I looked at each shot to determine:
A - quality; I tossed anything unsalvageable, and kept folders for things that would be perfect, with minor tweaking
B - topic (hers were many!)
C - chronology
As I sorted, we'd confer on tweaking options, according to what she was willing to do. If something only needed minor cropping, she often left that to me. If it was a lighting issue, that was more of an 'artsy' thing, in most cases, so was left to her. Editing out things that could detract from the shot, like a power line, an unexpected/ accidental photo bomb, etc were divided between us according to time requirements, skill, etc.
All of this sorting took a lot of space, too, but in the long run, it saved untold gigs, and made finding specific pics much easier. We researched many
online tools, to help sort them all out, and hands down, Dropbox was the best one, for our purposes, because it was fairly inexpensive, shareable, and infinite folders and files are possible. But, they key for us, was moving things off the hard drives, as we went. That did a couple important things. First, it freed up space on the hard drives, for photo dumps, to add to my never ending job security. But, just as importantly, it helped us keep track of exactly what had been curated, and what hadn't. When two people are working on something like this, and at different times, speeds, and decision making abilities (anything I was unsure of had to be deferred to her, lol), keeping track would otherwise have been a nightmare. Ymmv... Good luck!