I am curious to know.....since most State Code requires the use of backflow devices on commercial and residential irrigation systems......does your state require you to be backflow certified to even attempt this service?? Shallow well systems and such usually don't require it unless stated.
Check valves, drain valves and other simple irrigation components need to be addressed.
Just hooking up a compressor at 80 PSI for PVC systems.........using whatever compressor you choose isn't all that easy. If you must do this make sure the compressor has a hand adjustable regulator valve for fine tuning on the air pressure. I have a portable generator to run my compressor as most backflows aren't where they are easily accessible.