I just installed a system using PGP rotors and red nozzles. I have static of 45 psi and 12 GPM (on interior 1/2" line hose bib)...exterior main line is 1" and we are tapped in a within 1 foot of that entering the house with 1" to supply the system. I balanced the system and plan to do an audit this weekend to better determine the watering duration. Currently I use the following nozzles: 90deg - #2 180deg - #4 270deg - #5-6 360deg - #7 Irrigation tutorial suggests: #3,#6,#8,#9 I am almost exactly 75% of the GPM recommended on irrigation tutorials. Currently running 25min/zone w/ 6 zones and 4 heads per zone. My most exhausting zone is at 8.4 GPM now (charted for 40psi). I plan to renozzle a zone this weekend to see if I can bump up nozzles without ill effects from pressure drop. Currently I show about 40 psi on a hose bib while running the system. I figure I am probably already below 35psi at the heads. Sound about right? Therefore, I am not sure if I can up my nozzles more. What PR should I be aiming for. Around .5 in/hr? Thanks.