Keep in mind that any milk coming from a very small producer might be quite variable wrt fat content. Large producers will pool all their milk and if they have milk from 1000 cows, you get an average. Additionally, they will standardise the milk, by skimming it (usually). But if you are getting milk from Bessy one day and then milk from Gertrude the next, you may have *very* different milk.
I have to say that I disagree (to a certain extent) with Aris. My dad actually makes cheese in a really relaxed way (possibly similar to Aris) and he makes really good cheese that is delicious. Everybody enjoys it. It ticks all the boxes for what my dad wants in a cheese. It doesn't actually tick the boxes for what *I* want in a cheese, though. I have never had Aris's cheese, so there may be something they are doing that I'm just not understanding. But if *I* don't pay strict attention to what I'm doing, my cheese will be delicious, but it will not turn out the way I want.
Drain pH and curd structure are basically what the time in the vat is all about. It doesn't matter at all how you get there (and usually there are many roads to the same destination). However, varying those things will make completely different cheeses, in my experience. For me, that time in the vat is about paying attention to what's happening so that I can make small adjustments to hit my goals.
For me, the first step is to actually have a goal for the drain. It drives me crazy that recipes don't state this (even mine ;-) ). When I'm looking at videos of cheese making I first look at two things: the curd consistency at cut and the curd consistency at drain. I especially wait to see them take some curds out of the vat and squeeze them, or pull apart some curds (and I've yelled at youtube video editors that cut that out of their video
) Then I rewind and try to find out the temperature at cut and the temperature at drain (often it's being displayed on the machinery). This gives you the logic of the make. It's like the skeleton of the recipe. From there you add more details, building up the rest of the make. Then I'll compare that to recipes (and throw out most of them because they aren't even remotely close -- but to be fair, most of them were written before professions, traditional cheesemaking videos were easily available on the internet).