nitrous

ok.. i have a 99 silverado with 98,000 easy miles on it and i have a fuel injection nitrous kit laying around and was wondering what a safe number would be. i'm pretty much stock besides intake and exhaust. I dont want it too extreme and was figuring around 75-100. I don't plan on using it all the time i have a track vehicle... i just want that exta little bit when i want to play. I really figure a 100 shot would be fine but wanted some more opinions.
Thanks,
Derrick