I've got a sportsman fogger direct port setup i'm going to be running on my '67 camaro 469ci big block. I'll be running a seperate 1 gallon fuel cell with race fuel for nitrous enrichment.
Start out rich to be on the safe side then lean it out to make more power and check your plugs often..
Then you can either lower your fuel psi for the nitrous system, or rejet the setup to go leaner for more power.
Pull out a few degrees of timing to be safe also.
I'm going to run dual solenoids on the nitrous inlets just in case a solenoid ever sticks... They stick OPEN!

Its fine with me if the fuel solenoid stays open after i let off, but i don't want the nitrous still going!
Wire it up with a window switch, for example 3K rpms on 5K rpms off. 6K rev limiter.
Wire it with a fuel pressure safety cutout switch also, so if your fuel supply ever starves for fuel or drops pressure it will cut the nitrous preventing it from leaning out.
Wire the grounds for the relays through a WOT switch so you must be floored to activate the juice.
I've heard guys say "oh i'll just keep a close eye on the fuel psi gauge, if it drops i'll let off."

Good luck with that.
Hope you can let off in that fraction of a second that you're melting your piston.

And if you are watching your gauges you aren't looking where your driving.. with all that extra power.