Why bother? Adjusting the breakup screw on the nozzle can give you equivalent coverage. Besides, the two varieties of nozzles do not have the same flow rates. Now, if your 45 psi is the static supply pressure, and you have less that 30 psi at the heads themselves, then you can gain by making the switch, and taking the time to dismantle each head to readjust the stator settings, if changing nozzle sizes.
