Mani has been working like a maniac trying to earn the $$$$ ot takes to be as big of a pimp as he is, so I don't think he's been around the forums much, but I'll tell youwhat I know.
With a dual stage proportional nitrous set-up with a 75 shot that comes on with a window switch and then the second stage (125hp) is hit with a trigger button once the car goes into 3rd. The window switch shuts off the nitrous just before redline so that it won't be spraying when you shift.