wot/window switches are used only with nitrous, maybe methanol injection i dont really know, but they are there to make sure that you dont spray unless you at wot, high in the revs because nitrous at 2krpms would wreck your motor pretty wuick.
WOT(wide open throttle) switch is there so that the nitrous only sprays when you go WOT. The window switch allows you to set the RPM where you want the nitrous to spray, usually between 3k-6krpm's, thats the safe zone. I dont have a window switch but it is recommended for saftey reasons, actually you dont really need either but if you want to do it right get both.
Honestly you need both imho esp with a high pwr stick car. Without a rpm window if you hit the rpm limiter, no fuel, lots of nitrous bad deal. Miss a shift, tires spin, lots of reasons, you need it. I have a msd prog switch, its ok going to delegate it to the 69. jegs summit etc. Lots of better ones also but needs to be for coil on plug or prog. I would always set window top setting lower than rpm limiter was set.