Hello all,
I am currently redoing my sprinkler system that was already installed when we purchased our house.
The original install was in 2007 by a company that apparently is known to other local contractors for doing crappy work. I just located the valves recently by digging in the yard following the wires from the controller. I installed a valve box over them so they are now easily accessible.

The system breakdown was like this before I started changing it:

Controller-Weathermatic using 4 zones on the controller

Zone 1- Front yard, consisting of 8-9 Rotor heads (most of these are Weathermatic Turbo 3 4" rotors)

Zone 2-Back yard, consisting of 7 Rotor heads (most of these are Weathermatic Turbo 3 4" rotors)

Zone 3- Flower bed, side of house, perimeter of house, Consisting of 11 Weathermatic pop up spray heads and 4 fixed flowerbed sprays.

Zone 4- Sidewalk track of grass between road, consisting of 26 weathermatic pop up heads

My question is about spacing for MP Rotators in my situation given the current system layout.
Here is the current spacing of the rotors in the back yard. To get even head to head coverage with new MP Rotators I will for sure need to move the head that is semi in the middle of the yard.

The space on the edge on the sides is 40 ft which is too far for the MP rotator to throw.

To fix this, should I put two heads in the middle of the yard with the spacing suggested in the second image below? Or should I put 3 heads in the middle for square spacing like the 3rd photo?

I will be using MP3000 Rotary Nozzles unless I need to use MP2000.

Also there is one oddball head in the front yard that comes on with the back yard that I will be relocating to the corner of the backyard that has no head on this zone....

Current Layout of old rotors

Triangle spacing with 2 heads in the middle

Square Layout with 3 heads in the middle

This is was the approximate locations of everything before I started changing it. The static water pressure at the spout is 80psi.

The outer strip no longer as 26 weathermatic sprays. I swapped out to the Hunter PRS40 heads with MP Rotators. I used a combination of side strips, left end strips, and right end strips to cut down the total heads on that outer strip to 12 MP rotators. I have head to head coverage with that. I put them all on the inside of the strip spraying towards the road, which I'm hoping works out okay since they are supposed to spray an even rectangular patter. I will keep an eye out for dry spots.