[Vizcaster]

+1 on the .050" being the most likely size. The saddles on my American Standard and Highway One Strats both take the .050" but the Fishman powerbridge (tele style) has different setscrew sizes. Even though it's expressed as a decimal, you'll find .050" as the smallest wrench in an English/Imperial (Inch) set. I glued a broken one into a hole on the back of the handle of one of those tiny screwdrivers so it's easier to reach for (and harder to mix it up with the other sizes that accumulate for things like knob setscrews and trem-setter setscrews).