As always I prefer to keep quick save at F5 and quick load at F9 as that what's I keep in all games that support quick saving and customizable hotkeys so that my muscle memory knows which keys to hit without me really thinking about it (I save a lot).
Anyway, of course I can't change these because of whatever reason. I run Baldur's Gate Trilogy and I tried changing manually in the keymap.ini but while the BGconfig.exe accepts the change the game refuse to.
AutoHotKey has worked wonders for me. If you download it and tell me what keys you want remapped I can try to help you out by making a script. It's really simple though, you can probably do it without my help.