Thanks for the replies!, SFrazeur, GeoffHYL, and Maximus XXIVI!
As I said earlier, I can hear some balls collapsing when pressurizing, at around 20 psi. Here's a vid I found with the tell-tale sound:
My first attempt/experiment will be one week at 30 psi. I have - unscientifically - marked what I felt was the softest (flattest) and hardest balls. Before and after, I will do a 100 inch drop and measure the average bounce height of each (I believe official rules say ball should bounce 53-57 inches). My hypothesis/guess: I think pressurizing at 30 psi will collapse the softest balls and they will not improve in pressure/bounce height at all. But the hardest/highest psi balls should improve some (prayer emoji).
Another possible factor: I read that temperature may play a role with gas permeability of the rubber. I live in Hawaii and do not have air conditioning. So when we're out at work during the day and the house is closed up, the interior temp is probably around 90 degrees F; higher in summer. About 10-15 degrees cooler at nite.
We'll see...