This is the first time that I use rotary heads. I am watering a 64' x 22 area (all grass) and planning on using PGJ rotors spaced at 22 feet apart. That comes out to 4 quarters and 4 half circles. with the #1.5 nozzle each. 1.5 GPM X 8 heads =12 GPM. So I read the previous thread on rotary nozzle questons and it stated that the half circle nozzles need to be twice the size of the quarter nozzles to make sure you have a MPR. Do you guys recommend I just keep the #1.5 nozzle on all heads or replace the half circles with the # 3 nozzle. Any help is greatly appreciated. Thanks Hector G.