How much nitrous for a stock piston?

I picked up a used NX system for 200.00 last month from a guy close to me, it has the big noids (checked them & there good), bottle, lines & nozzle for EFI, i'm looking at a plate kit from (yeah i know) Procomp for 59.95, it has a 40 hole spray bar, bottle brackets (which i need), 8 jets, braided fuel line & fittings, i'm alittle leary because its from Procomp, but maybe its not so bad.

Thanks for the heads up on the other stuff, i'll look into it, because NX heaters are 200.00.

i dont know about procomp man, they seem a little shaky lol...for the money it doesnt hurt to try, but then the question is what if something happens to the motor?? either way though goodluck...and yea check out that heater, its the best one ive found for the price without paying name brand stuff