Nitrous fuel pressue info needed

Do you have an O2 sensor/readout in the car or available? I'd tune the kit so you get a similar AFR as the best runs NA.

Looks like the instructions for an NX direct port 75 shot is 20/20 at 5.5psi and 20/18 at 10psi. Those are usually really safe/fat so there is usually room to lean it out. If you want to lean it out, either smaller fuel jets or lower fuel pressure. Will have the same net result... less fuel introduced.