I’m with @sam on this. I would find it very confusing if I were to get notified that post #22 out of 200 sent me a notification because the OP edited it. It is old news by post 200 and likely isn’t very relevant anymore. Allowing it to be edited, likely makes posts 23-26 meaningless too (or has the potential to).
We have a 5 hour edit window on our setup (it may be a day now), and we’ve yet to have any complaints. We even experimented with a shorter 30 minute window and we got several complaints, so I think we’ve found the sweet spot for our particular community.
You will just have to find that sweet spot for yours too or make it outrageously large so it feels like there isn’t one and deal with the consequences whenever they come. An edit in the middle of a topic is never going to be meaningful to the community as a whole, it will only be suspicious to the staff (and the solution for that already exists, shorten the edit window).