Yeah, I've learned this, also. I'm trying to find my own way with some by looking at the difference between yours and the defaults and why it makes a difference. I've tried using the raceline and other setup guides but none of the tweaks I try that they suggest really seem to make the "critical" improvement so I've just started buggering around with stuff and trying to assess what the change helped with. Interesting that you change gear ratios and braking effort - these are two things I hardly ever touch. Maybe that's where I'm going wrong!
i always go straight in and drop the brake pressure down to 75% sometimes down to 50 depending on the tracks resistance. as i suffer from a heavy left foot on the brakes and tend to lock the wheels, i find that means i brake a tick earlier than most so tend to run a slightly shorter gear aswell. its each to their own but again raceline helped me alot in learning to understand what does what and even down to the section that say things like under-steer mid bend and then lists things you can change to try and help.
think i picked these up when you originally posted them but thanks again southy