I think I posted the general values on the other board. The values are confirmation of visual and sensory indicators for me, and used in combination with heat and time schedules. For example, say I’m making a swiss style cheese and the milk is 6.6. For swiss, you need to drain at 6.4, or the body is not appropriately plastic. That means I need to cut and cook enough to expel the whey quickly, yet retain moisture. That combination requires very little ripening time, a thermo culture, small curd size, high temps, and low multiplier. Say pH had dropped to 6.5 after rennetting and waiting, but the time was not there yet to cut. I would cut.
The above is a bit of an extreme example because there’s no reason pH should drop so much unless the starter amount is too high or the milk is not fresh. But those are the considerations that go through my head. I usually only adjust timing to hit the drain and brine or mill targets. Those are pretty much the same for most cheeses, except swiss types. I drain at 6.2, maybe 6.1 and brine at 5.4.
pH is an important indicator especially at drain time because it directly influences the calcium phosphate remaining in the curd. At high pH, a lot more is left. If you drain at 6 vs 6.2, it makes a pretty big difference in the final cheese in terms of paste, moisture, and flavor.
pH is also important at salting because you don’t want it to overacidify. And the acidification rate/curve is important. That’s why a lot of makers will check pH over and over—to understand the acidification rate, which can vary with starter and milk.
For parmesan, use a small curd size (whisk it a lot), 1x-1.5x multiplier, heal the curd for 5-10 mins, then cook, stirring so curds don’t mat. Drain around 6.2… dry grating cheeses are more forgiving with drain pH, so if it’s 6, that’s not terrible. After you hoop and press, pH should be around 5.2-5.4, and then you brine.