As it turns out, there are just too many variables to accurately decide why one pond will come up 8" with a 4" rain, and another a few hundred miles away will come up 4" with a 4" rain. I realize the math side, that you have a given amount of drainage, a given amount of rainfall, and a given pond dimension, and all the rain has to go somewhere.
The bottom line for me is, if I get enough rain, which turns out to be, just the average rainfall, I should be ok. Prolonged periods of drought will drop the pond level every week, and unless I want to introduce a man made water source, I will just sit back and watch what happens.
Seems like a bit of a waste of everyone's time here. Sorry about that. No majic bullet to bring in rain water. I've done all the diversion I can, I just need rain.
Thanks everyone.

9 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (going away), SMB, and HSB (only one seen in 5 yrs) Restocked HSB (2020) Have seen one of these.
I think that's about all I should put in my little pond.
Otter attack in 2023