Yes, and no. This option does indeed work, for FS-UAE itself. But using it with FS-UAE Launcher will have less of an effect, since FS-UAE Launcher also currently extracts/copies disk images to a temporary directory before launching FS-UAE. So the net effect is that floppy overlays are not used, but instead, modified .adf files are saved in the state dir instead.
I'll have to either make FS-UAE Launcher respect writable_floppy_images too, and behave differently if set, or do something else to support this use case. I'll think on what's the best way to proceed...
Only 100% is supported, other speeds may or may not work depending on the game. The online docs are updated.
You must run a simple file re-scan in order for database entries to reappear, the database schema was updated in the development version and there is no automatic database migration. Oh, and keep in mind going forward not to use the stable thread for devel-version issues, or people might get confused
EDIT: Yes, I see from the screens that other settings are missing. Perhaps you downloaded the portable version? That version will use its own settings file... to keep it portable...