Default Battery saving on Defy+ /w KitKat CyanogenMod - 2G vs 3G?

- Does using 2G (or EDGE?) networks save battery life on Defy+? For light data use, of course. I could not locate any info in the users guide. Nor for the KitKat build.

- Any other battery saving tips? For example on some devices turning on 'battery saving' in the menu will actually drain it more, so it's a controversy.