Question
How to adjust the sprinkler heads on systems and which to use?

Answer
Cal,
First, let me apoligize for taking so long to answer you. I have been deathly sick with the flu and then came Christmas. I hope I am not too late.
Now, as far as how to adjust sprinkler heads the problem is almost every model made by each company adjusts differently. Nearly every one also requires some kind of adjusting tool made specifically for that type of head. It can be quite time consuming and aggravating trying to do it without the right tool and instructions. The good news is that most of the time you can find a web site of the manufacturer to help.
If you are asking which to use and wanting the easiest one to adjust that is reliable I guess you could go with the Rainbird 5004, which is sold at hardware stores here under a different model number, but the same head. The sprinkler head with the best track record is probably the Hunter PGP, which is not as easy to adjust, but they seem to last forever. Cal if you have questions about a specific make and model of head you are having problems adjusting let me know. But there are dozens and dozens of different heads and to start going thruogh them all would only confuse the matter. Let me know if you need more help. I promise to get back to you quickly as I am no longer sick as a dog. Thanks, Jim