A pump used to boost city water pressure can have even more variation in flow. If the city pressure varies at all, the output of the pump can also vary. It can be even more important to control the flow of a booster pump than it is a supply pump.
There are plenty of valves available that will do 70 PSI. But again, if you need 70 PSI, the back flow device is just in the wrong place. The CSV is just a tool that can make your job easier and enhance your irrigation system designs. If you see it as an insult to your ability , you are not utilizing all the tools at your disposal. Kind of like someone saying, "I would never use a computer, because it is insulting to think I need any help with spelling, grammar, or math skills".
There are plenty of valves available that will do 70 PSI. But again, if you need 70 PSI, the back flow device is just in the wrong place. The CSV is just a tool that can make your job easier and enhance your irrigation system designs. If you see it as an insult to your ability , you are not utilizing all the tools at your disposal. Kind of like someone saying, "I would never use a computer, because it is insulting to think I need any help with spelling, grammar, or math skills".