I saw this thread so decided to give it a go. I haven't done any sim racing since early in GT6 (7-8 years). Surface, curbs, physics have changed quite a bit so takes some getting used to and I've never been an "expert" on this circuit. The car is a pig also.
Anyway, spent several hours over two days going through each sector and getting gold in each, then getting close to the example time then getting gold without feeling like I was taking too many risks. I agree with someone above who said sector 8 is the hardest. Sector 1 is just as hard in reality, but that one you can take risks and throw away easily so sector 8 is in it's own league IMO.
The harder part was putting everything together for one lap... my biggest problem at first coming from individual sectors was getting the full flow of lap. I found myself lost a few times going into corners not remembering where exactly I was... so took 5-6 full lap attempts to get a solid mental map of entire circuit before I could start pushing and laying down decent laps with ghosts I could use as a reference. In the full lap sector 8 again was the biggest issue. So easy to lose time if you go less aggressive there and very easy to go off, far enough into lap it was dangerous to risk too much. Anyway, getting a decent ghost time within realistic range of gold was the breakthrough as said above.
NOTE: When I took a break, even overnight, just put PS4 to sleep so I could resume and not lose my ghost. Reading above not sure if my car started to suffer from old oil degradation, but doesn't seem so since I wasn't really losing significant time to ghost on straights.
Anyway, 2nd day of doing full laps I beat gold time (TCS 1, ABS normal, no counter steering assistance). Scruffy lap overall to be honest, but most of my mistakes weren't ones that cost a lot of time, but they add up over six minutes and just barely made it with 0.5 seconds to spare. lol.
I was a fairly fast TT driver in GT5/GT6 so feel like I'll be fine in the other circuit experiences (as far as the other long circuit, I completed Le Mans fairly easily and with much more margin as I was more proficient on that circuit from GT6). Nordschleife was a challenge for me and it feels good to gold it, but also glad it's over.