FWIW:
I did this one year and was very proud of it.
Until the tomatoes got every disease in the book from the wet leaves and splashing water.
Never again. Now I drip irrigate.

Perhaps I should mention this is for a lawn . . .

Life,

Take a look at the Hunter Heads and any other google candidates. We can comment on any one you find. Some posters have strong opinions on what not to use. Are you being cost conscience or sound sensitive? Do you prefer impact sprinklers or want more rotor type? There are basic decision to make on this. What type were the ones you had? Aloha

The sprinklers I had were Accurain. I was thinking that some brass Rainbird sprinklers would do the trick. I was planning two each per post with a ball valve ahead of each sprinkler, allowing more adjustability than the stream deflector alone.

The rotors are interesting, but I'm not sure they do as good a job at watering all the way from the sprinkler to the maximum distance.

HiLife,

Here is an idea. Try one sprinkler from different manufacturers or different types from the same manufacturer and test the coverage for each sprinkler by placing cups out at intervals from your post and the same time period and measure the depth in each cup. Pick the one that covers the best and post your results here for everyone's benefit. Why do you put two sprinklers at each post? Two 180 degree sprinklers or one 360 degree? You must have good pressure and flow to reach 25 feet. What is the pressure and flow of your system? Aloha.

That sounds like a good way to test coverage. The reason for the two sprinklers instead of the obvious single 360 degree solution is to allow for each to be set for a different distance, and more practically cover the area to be watered without a great deal of adjust, water, readjust.

The Accurain sprinklers had the ability to map out an area for distance vs rotation, so my replacements will do best if I provide for some ability to adjust distance versus rotation. Two distances (sprinkler heads) are better than one.

I have 'pretty good' pressure and flow. I think it is 60 psi, and there are only three posts with 3/4" copper all the way to a 1/2" soldered male pipe adapter at the top of each post. I'm not sure I would run all 6 heads simultaneously.

Hi Life,

Do you know your flow? Fill 5 gal bucket and time it. The heads literature should let you know the throw distance and flow for 60 psi. Then you can calculate what you can run on any one zone. 60 psi is very good pressure without stressing the head itself. Aloha.

I put the first two Rainbirds on one post. I actually have the opposite problem from what I expected; too much distance. I am deflecting the stream downward with the flap, and turning the screw in to further scatter the stream. I guess this should come as now surprise given the 4' high mounting.

Fortunately, I put a ball valve ahead of each sprinkler, so can turn the flow/pressure down there as well. Adjusted to the minimum flow that will operate the impact sprinkler, the results are pretty good. I can water the entire front yard by making one adjustment to the set of two halfway through a cycle. No, it's not automatic, but I did not have to install an entire new piping system. And it sure beats dragging a hose and sprinkler around the lawn 10 times per watering.