Thank you both so much for the help. I really appreciate the explanations.
So, what I'm understanding is that the two ideas are
1. install the game twice essentially, have one running the latest EA update so you don't lose the last women's teams (if EA has ever even bothered updating them from release) and the other running the MW mod version you want to run. Then when an unknown save exists and is claimed to be corrupted you just cancel out of that and load the save you want.
OR
2. have the one install but copy in and out the saves and also the db files so everything the game needs to play whichever version you're trying to play is there whenever you need it.
Is that it?
Now, furthermore, I actually have no particular allegiance to MW. I just don't know how to add what I want manually. In an ideal world I'd have
- kits, adboards, overlay graphics (scoreboard, logos etc)
- squads, but I tend to fix those myself with CM16 and I find EA does a good enough job
- the tournaments I want (I never play any seasons other than Ligue 1 or Premier League and then other tournaments like CL)
So can you just add these yourself? moddingway is easy and a one-stop solution but I always wonder whether I really need to have EVERY league in the game edited. I'm just a bit annoyed by clutter, clearly a bit OCD, and I find having things modified that I'm not gonna use sort of pointless. regularcat once told me, when I was using MW to get the Copa America last year that he could just get that one tournament and apply it to a country I wasn't using. That kind of simplicity sounds fantastic to me. Like I said, I play England and France, I don't really need the entire Italian League perfectly set up, you know? I play my seasons in career mode with an edit that I do that impedes all transactions and injuries. I don't pay attention to anything happening in other leagues and the Champions League and Europa Leagues not having perfect squads doesn't bother me.
Last question about saves... So each DB will only read the saves made under it. So when I pick, however of the two methods I choose, to use on DB, I have to put the corresponding saves back in as well. And that's that? If I don't I'll get that corrupt save error.