I didn't mean you should create a new topic. Still, the only way to set it up if you have no assembly language knowledge is to wait for it be implemented by someone. It's not as simple as games that save with a battery. I'll try to see if I can figure it out from the FCEUX source code, since the explanation on the wiki isn't so hot.
Edit: Nevermind, there's a nice code example that I missed the link to on the wiki. It turns out the explanation on the wiki is fine, it's just very, very different from most mappers I'm used to.
It's a pretty wild system. With battery saves, it's basically like write to "extra" RAM and you're done. And the way to write to extra RAM is the same as writing to "regular" RAM. This requires a sequence of like 8 writes where most things need three at most (like updating a single "graphical" byte needs 3). And the code for this apparently needs to executed from RAM, it's actually a bit scary to think about and I've been doing this a long time.
The good news is there's kind of already a library for it which is the nice code example I mentioned: https://wiki.nesdev.com/w/images/f/fa/Flash.asm.txt
It's there if anyone that comes across this topic feels like attempting it.
Edit2: Actually now that I'm thinking about it MMC1 is five writes to swap, and reading the controller is two writes then 8 reads so what this is doing isn't totally out of the ordinary. The code apparently needing to be in RAM is still odd, though. Anyway, forgive my rantings, it was just quite interesting.