Logarithmic is the wrong word, what u r asking is the club linear.
Well it is the closest to linear u will get.
So as said above 75% power will give u 66% distance, and that ratio works basically for all 3 cleveland wedges.
I hit 60% power on the 64º wedge for 30 yards - no spin required. ( Full shot )
Below that distance, I use chips, picthes and flops.
Never forget: a flop from the fringe will skid 6 - 8 feet further than what u expect.
So e.g. a 12 yard flop from the fringe is normally 75% from the fairway, from the fringe I hit between 70 and 72 %, full BS