SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

I have recently redone a rising slope in my backyard with drought tolerant plants (I live in coastal S. Cal). However, I still need to water periodically during dry times. I also had my connection to the street modified, but now have 110 - 120 psi. I have old Champion 3/4" and 1" anti-siphon valves at the bottom of the hill, and the two 3/4" are now leaking heavily. I've replaced the gasket in the body, but that hasn't helped. I read that the anti-siphon feature is useless regardless because the valves are below the sprinklers. SO - do I need to reposition the valves at the top of the slope? Should I just replace the 3/4" valves with larger ones (assuming that water pressure is an issue)? And do I need to stay with Champion or can I go to different valves?

Thank you. I'm checking with a local landscaper on the code.