If you're going wet with a window you can do a 75 shot without changing spark plugs. Once you go above a 75 shot to 100 shot you're going to need different plugs and tune.
I've been thinking a lot about the same setup for mine.
The window is definitely the way to go. Don't forgot about the bottle heater, pressure gauge with relief valve and so on.
You will have to get a new tune for the nox!!!