EZ Flow Yes, and Irrigation is considered High Hazard Most of the time.
I would like to say 100 Percent of the time, but some jurisdictions approve the double check valve as an appropriate Backflow device. Double check valves are only for a low hazard situation.
Pressure loss will be anywhere from 8 to 15 lbs depending on flow rates and manufacture of the RP.
Good Luck.
Oh yeah the gauges to test backflow devices are usually about 800.00