With a handgun, if you want stiffer trigger pull (i.e. go from 3 pounds to 6 pounds) you get a stiffer spring. If you want to convert a revolver to double action only (where you can't **** the hammer for single action; all you do is pull the trigger) you get a lighter spring because there's no need for the hammer to go all the way to locking position (because the part that locks the hammer has been chopped out), and because it makes it quicker/easier to fire from double action (making it quicker and safer).
So with a Floyd Rose, instead of replacing the old spring with new and stiffer springs... you add another spring (or two or three) to the preexisting springs? :confused: