I have an existing system that, to be frank, was the product of a low-ball estimate. Now, due to issues with a fence install (the installers dug through two zones), I have an "opportunity" to replace and add a few zones.
I was certain I read on irrigationtutorials that one should place the valve of a zone close to the first head in that zone. I read that awhile ago, but not cannot confirm that's what it said.
I was planning to reconfigure one zone and add two others. All three proposed zones are towards the rear of the lot and were previously serviced by one zone with a valve WAY up with the others. All of the valves were clustered together, regardless of what part of the lawn they serviced.
I was going to remove the existing valve (to a currently dead zone) and run SCH 40 PVC towards the rear of the lot and break off for the new valves and zones back there.
you will be considered to be in a northern climate, so no big reason not to use poly pipe, and to not keep the valves grouped together in a single valve box