To make the default value of Rate of Fire be the same as vanilla (1.5/sec), do this:
In data.lua, change 60/var3 to 40/var3
In settings.lua, under "laser turret fire rate", change default_value=40 to default_value=1Â
In locale.cfg, edit the custom-laser-attack-speed verbage to read "Each unit is 1.5/sec."