Your Youtuber video led to this one:
These videos are an example of a little knowledge is dangerous. He starts with an incorrect point and then a bit later quotes some drivers who if he listened to what they were saying, he would realise that he was wrong.
Just to be clear, F1 tyres produce the greatest grip when you are cornering and braking or accelerating and cornering, not in a straight line. Which is what Mark Donohue's comment relates to. Both in terms of stability gain (very tyre and setup dependent), but also in terms of grip gain. Mark is correct that you want to be out in the combined cornering and braking and accelerating zone (Peter's tyre circle is basically correct apart from the pure longitudinal; braking and accelerating). This is where Ayrton Senna was the best driver that I have seen data for and out driving on the race track. And this is where it is most difficult to drive a car.
Peter Windsor does make some good points himself and does quote some useful comments by drivers, but completely misunderstands some of the reasons as to why the drivers do what they do.
He also talks some complete rubbish about simulators, which do allow the drivers to experiment with their line and control through the corner (especially with thermo mechanical tyre models in use). But he is correct to say that during the race the way the car reacts to inputs is changing slightly all the time at any given corner, due to cross wind, tyre temps, slight inconsistency of line, tyre deg, tyre marbles, other drivers going off line and leaving stuff on the corner etc.
In simple terms the best drivers are managing the car into the turn so that they can get the best exit, as the faster they are than any other driver on the exit, the faster they are likely to be all the way down the straight. i.e. the drivers are optimising everything for the exit to maximise their acceleration. This is why corner exits from low speed corners have a massive impact on laptime, whereas high speed corners and corner exits have so little effect on laptime.
Very simply, the driver that maximises acceleration around the lap, will be the fastest.
