DEcosse
If it's no Scottish it's CRAP!
... I do see the explicit setting for 4-strokes/3 cylinders, which is nice....
the number of cylinders only becomes applicable if the signal is coming from a distributor (remember those?
With a coil per cylinder, it does not matter whether you have 1 or 12 cylinders (or three of course!) - you just get one pulse every other revolution off that signal.
i.e. as far as your R3 tach application is concerned, you treat it like a single cylinder NOT a three.
Note that the mini one posted by Corey is a dirt bike type one i.e. single cylinder 4-stroke application