Optimal tire pressure will always involve some guesswork.
Last week's urban group ride bashed across some unexpectedly rough railroad tracks. Two riders got pinch flats. One weighed no more than 110 lbs, probably less, on a lightweight carbon fiber bike with 700x23 tires, and said her tires were fully inflated. I checked the undamaged tire and it definitely wasn't low, especially for her size and weight. Classic snakebite tube pinch marks on the flat.
I weigh 150, was riding a 25 lb steel road bike, and had my 700x25 Conti Ultra Sport II (cheap but good) set to 75 psi front, 90 rear. No problems bashing across the same tracks. I can't bunny hop but may have unweighted the bike a bit at a crucial moment, I dunno.
In the past four years, typically running tires on the low side for comfort, I've had one pinch flat. And that was pretty extreme. I was squeezed between a parked truck and another oncoming truck that veered into my lane. I was focused on not getting squished and bashed across a brick I didn't notice. Classic snakebite, my first ever. I doubt any tire pressure would have helped in that case. I was just happy the tire and rim weren't damaged.