I am a newbie and trying to make tcs 0 as well. My opinion goes to car group instead of tracks as well. Still on progress but here is my suggestions:
> Try with Gr4 FF cars. When you hit the throttle, Gr4FF cars are not willing to spin. But you may observe some understeer. After some laps, you would be good to go. Then try other Gr4 cars. You can start with 4WD cars. Then in time, you can go to MR. When you start to handle Alfa Romeo 4C Gr4, Gr4 is done!

> For Gr3, I started with Porsche 911. I do not know why but this guy was so helpful in TCS removing. Interestingly, while I was using TCS:2, my favourite in Gr3 was Beetle
> Watch some videos but slow motion. You start to observe when these guys are hitting the throttle and hitting brakes.
> TCS is not nemesis; it is helpful in so many cases. If you are pushing your lack, you can use it in the race from time to time.
> I could not find TCS more than 2 beneficial. Even 3 is too much.
By the way, my other suggestion could be, if you are not using, try to use MT instead of AT. Still, I do not know how, but MT made my removing TCS process much easier.
Helpful track and car combinations for me was:
Gr4: Audi TT - Dragon Train Gardens
Gr4: Huracan - Fuji
Gr3: Porsche 911 - Autodrome Lago Maggiore
Gr2 and Gr1: Still on progress