My suggestion is do some reading in this section, do some research, contact vendors.. then make your decision.
There are three ways its done typically.
Fixed point whereas at "X" PSI it fires the pump at a preset pressure.
The other is a multistage whereas you utilize a couple solenoids to fire a couple nozzles at different boost levels.
The third is a progressive which as the boost rises increases the rate of flow out of the pump.
Then you have types of pumps, types of nozzles, ease of installation, etc to consider.
And lastly always weigh in reliability in your decison.
Some argue that a fixed point on a track car is all thats needed. Some say a multi-stage is better. And others like myself say a progressive is best. This is part of your research, so you can be at peace with yourself after you have made your decision.
This is a technical forum, I wont do mine against anyones debate. That ultimately is the buyers job
HTH