Call me dense, but I don't understand what you mean.
I took the pump's curve, and reduced the curve by what the heatercore would do, leaving the rest of the pressure available for this nozzle (well, it includes all the tubing and fittings, but I'm assuming that that will be relatively negligeable).
If myv65 was here, I'm sure he'd show us how to do it the right way (but he's probably still busy laughing
).
The next step at this point is to calculate what the nozzle should be like.