@mbriganti the closest...put a Callaway tip on the Ping shaft and Whamo there you go.
I don't know anything about Ping stock shafts so you're best off to look at all the specs for that shaft and find a comparable shaft that Callaway offers as far as weight, bend point, torque, etc.
@mbriganti Can you go somewhere and get fit? Even if all you can do is hit a demo driver with the different stock shafts you'd be better off than trying to match the Ping shaft.
As as a fitter once told me...Callaway has a stock shaft to hit it high, hit it low, hit it in the middle and one for the really slow swings. One of them is bound to work for you.