Interesting. Yes, my total time is the flocc time multiplied by the multiplier. So for a flocc time of 10 minutes and multiple of 3.0, the total set time (from adding the rennet) is 30 minutes. The idea for cutting early is that the earlier you cut, the faster it will drain. Normally you will also loose fat because the globules are trapped between the casein micelles. But for homogenised milk, there *are* no globules. The fat is actually wrapped around the micelles, which is why the rennet works so poorly (IIUC). So there is not really much danger of that. And in fact, you can see that homogenised milk has *very* clear whey most of the time as a result. The "shaking" seems like a good idea. I think I know what you mean. I'll have to give that a try.
In terms of hitting pH targets, I don't have a pH meter either and hitting drain targets is a lot of guess work. However, I do a couple of things to inform myself. The way the curds stick together is completely different depending on pH. The higher the pH, the easier they stick together. You may have seen Gavin Webber suggest squeezing a handful of curds and then pushing them apart with your thumb. This is the test to get you to about a pH of 6.0 (I *think*), so it's a bad test to use if you want to have a higher pH than that :-) Higher pH the curds will stick together more easily. Lower and they will fall apart.
Similarly, curds will form from acid at 85 C at a pH of 6.0 - 6.1. Take some where (possibly all of it) and make ricotta out of it. If no curds form, then you are above 6.1. If curds form, but they sink into the whey, then you are below 6.0. If I'm making cheeses that are really high PH (like a tomme or alpine cheese), then I usually wait an hour or so and then make ricotta. This just helps me dial in my process. It's all estimation, but over time you get a feel for it.