Eddie,
That's a very useful number to have...when another dry spell hits you will know exactly how much rain is required to fill it back up...or very close estimate.
I'd be interested in your number if you don't mind. The big(relatively)pond I built several years back has a very low amount of drainage....something like 3 acres of watershed for a 4 acre pond. My number for that pond is 2/1, i.e. 1 inch of rain wil produce a 2 inch rise in the water level. On another pond I built with lots of water shed, not surprisingly a 1 inch rain can result in an 8 inch rise, but it fills up so fast that I haven't been able to calibrate it well.
Ok...this is a little "zen" like, but your pond will reach that spillway and water will go over it for the first time only once....for me that was a moment to cherish and always remember.
