I hate to take issue with your advice, because I can see how what you say could work if you drive the car correctly. If the timing is such that the engine pings under the circumstances you describe AND you back off the gas enough when climbing that hill to prevent pinging, I might go along with it.
The reason I take issue is that ideally, you should NEVER here your engine ping. Pinging is preignition. Under normal combustion, the fuel/air mixture burns SLOWLY. Preignition is the fuel/air mixture igniting and burning virtually INSTANTLY in one concentrated location on the top of the piston. This puts a strong impact on one small point on the piston top. It is as if you swung a very large pick shaped hammer as hard as you could against the piston top. I have seen preignition put a hole through the top of a piston.
For this reason, it is important for your engine NOT to experience preignition at all.
Have a great day,