Most people I've spoken to dont seem to think getting a feel for the track via a console game fist helps. But after doing Oulton on Toca 3 I think it really helped me get going quickly and I'd already decided which corner not to tempt fate on (and true to the game, all people crashing on the day went off on the one I kept losing it in the game on!). Maybe I'm a slow learner, but I've never managed to even get a feel for a new track from the sighting laps before. however with Oulton I was ready to go.
I cant emphasise enough the importance of getting to the track on time for the first briefing, and therefore not missing the sighting lap and then being able to get out straight away.
In the afternoon there may be less cars on track, but the first part of the morning session is essential for getting your confidence up. Because the cars get quicker through the day as people learn the track and push harder, its good to get out early whist cars arnt pushing 100%. This enables you to also take it easy. If you start half an hour in having missed the sighting laps and track time you will litterally be going so much slower than the now fast pased field, you spend all your time being passed and not being able to get a feel for racing lines and braking zones.
That said, saving your brakes and petrol for the last 1.5 hours can be good as many people have gone by mid afternoon and the track is quieter.