My pressure is only about 8-9gpm, and 60psi. I was able to put 3-4 Hunter PGP ultra's, or Rainbird 5004 rotors on each zone, with 2-3 gpm nozzles each depending on # of heads a zone, 6 zones total. I succeeded in head to head coverage except for a small area in my front yard due to some big @$$ roots from oak trees.
All areas are different as far as installation.
In my area, all you need to do is have utilities marked if you are doing it yourself. Since we have lived here for over 30yrs, we know there are no buried utilities on our property, except for our own septic system and LV lighting wire, especially since we are far from the road. Electric, cable, and phone are aerial, and gas was installed on the opposite side of the street 4 yrs. ago......but we are all electric. We still called, and they said they didn't need to come out because we have no history of buried public utilities near our property.
We asked about connection to water main, they said just to have a PVB installed, especially if we are connected to city water (we have well, but still added a PVB for peace of mind), and electrical, they said they don't issue permits or inspections for low voltage wiring.
Again, this is just my area. You should always ask. Some areas have no guidelines, some may have them where you need a permit just to replace a sprinkler head!