See the link I put in #16, and look at page 5 and understand that 1 hp 12 gpm is not appropriate. The graphs on page 4 have more info, but they are harder to use. Worth looking tho. The head has two parts-- depth to water and pressure head. Pressure head is about 140 ft at 60 psi. So add 140 to the actual water depth to compensate.
So in that family, 1 hp 5 gpm, or 1 hp 8 gpm. Your 12 gpm is almost strong enough, so the 8 gpm seems like it could be a good match. Its flow would decrease as the water level fell close to the pump intake, but that may be an advantage.
Other pump families have 7 gpm pumps.