Some suggestions:
- Check water ptessure. If the water pressure I’d more than 40 psi the spray pattern of the spray nozzles will explode. If high water pressure install pressure regulated spray bodies that regulate pressure to 30 psi
- Not good to mix sprays and rotors because they have different precipitation rate.
- Install Toro Precision nozzles (female or male thread) with pressure compensating disc. They have output of 1 inch per hour.
- Remove rotor and replace with additional spray bodies for matched precipitation.
Brown areas usually caused by low pressure, high pressure or heads spaced too far apart. I suspect you have high water pressure.
You can buy an inexpensive orbit pressure gauge at home Depot or buy a hunter mp spray head checker and buy a pressure gauge to screw into the head checker. I think you are a contractor so you can get these things at Ewing, Longhorn, Horizon, Site One, etc in the north Texas area if that is where you are located. I installed the Toro Precision nozzles and 1800 Prs heads and my coverage is outstanding now.