Hi Wet_Boots!
The old system had 3 zones for the 6 pop-up sprinklers. If I can manage with one zone, that will leave me the other 2 with the anti-siphon valves, etc. to water the areas that are not presently covered.
I may have read it wrong. I assumed that with 50 PSI with the 5 nozzel it is 2 gpm, so my total for the 6 PGP's should be 12 GPM. As you mentioned 4 will be 90 degrees, and 2 will be 180 degrees.
Thoughts?
Emil