A 10 GPM, 1/2HP can only build about 231' of head which is the same as 100 PSI. 1 PSI of that will be lost for every 2.31' to the static water level. You need at least 70 PSI to work with a 40/60 pressure switch. This means with a 10 GPM, 1/2HP pump the water level in the well cannot be deeper than about 76' deep, or there will not be 70 PSI at the surface.
Now if you have a 3HP, 10 GPM pump it can build 930' or head, which is the same as 402 PSI. But a 10 GPM, 3HP is made for a deep well, so if the water level is at 700' there will still be less than 100 PSI back pressure at the surface.
Unless the pump is WAY oversized there should always be less than 150 PSI back pressure from a CSV. However, as long as the pipe can handle the pressure, even 300 PSI back pressure is not bad but actually good for a 3HP, 10 GPM pump. In cases where the pumping level is 700+' deep but the static is at 10', we use two CSV1A valves to stair step the pressure down from 300 to the 50 PSI constant that is needed with a 40/60 switch.