I used -4 BB for this lap you should use somewhere around the same because if you dont you will kill your front tires even in a 15 minute race and loose a lot of time in the last 2 laps.
T1 go late on throttle bcs of the exit offtrack
T3 early apex and early on throttle be careful with the offtrack on the exit 
T5 go late on throttle else you will understeer off the track / get a slide and loose time
T 7 / 8 / 9 Brake at about 125-130m and cut the exit curb on T9 to get the best run

T11/12 trail the brakes long bcs the exit gets very tight -> late on throttle. You have to be very careful here else you will hit the grass and loose a lot of time!

T13 watch out to not get a slide so be careful on throttle application 

Generally you should be making sure to shift just before the car hits the limiter as that gains you a lot of time in the McLaren!
Driving wise you should make sure to have a peak braking pressure of just under 100% so in the range of 90-95% and then trail of that peak pressure as soon as you start moving your wheel.
And once again as a reminder this is a fixed setup series so the only thing you can adjust is the brake bias for which i will always provide the setting i used!