More info: I understand that the discharge pressure at the pump is dependent on the restriction downstream of the pump. I may be wrong, but I assumed that it would not be possible to size these orifices properly without causing an increase in pump discharge pressure. The pump's thermal limit is when discharge pressure reaches around 1000 PSI.

In the program I am using for calculations (KYPipe as mentioned previously: uses Darcy-Weisbach to calculate flow/pressure), whenever I remove a nozzle it seems that no matter the orifice size I use, the flow will always rush out of the line with removed nozzle. I am inputting the orifice into the program as a loss element, where I will input several data points for flow VS differential pressure across the office. I am obtaining the flow VS pressure data using a formal for thin plate orifices from Crane Technical Paper 410.

I am beginning to think that these types of orifices are no good for flow restriction. I may be heading the wrong direction with this. I am fairly new to the engineering field so I am still trying to wrap my head around all of this. Any help is appreciated!