[Ted Haggard]

The tank is big enough for the whole race distance 

I get very different results. 
just jumped in and did 40 laps in total.
default setup, no adjustment to pressures or anything. Put in 50L fuel, SS front left was almost permanently overheating but keeping at low 32's in first 10 laps then last 3 laps dropped into the 33's. 
My race essentails app said all tyres were on 0 life, car was still going but ran out of fuel - 3.8L per lap. 

Swapped for the Softs, less overheating, high 31's with a best of 31.6 right on the 13th lap (again just testin with 50L fuel)

Put on the mediums, consistent high to mid 31's, more consistent than the Softs due to no overheating. 

After setup tweaking there's probably another second to find, lets say race pace is a 1.32 average, thats 150L needed. Fuel tank holds 130L...
so its definitely a 1 stopper. 
I might experiment with a longer 1st stint on mediums and a short flat out second stint on Softs. 
I was testing with Optimum track, 26 degree weather temperature, weather clear, 12:00 time. 

As for Q pace, i kept default setup, put in 10L to see what car was like, did a 30.4 immediately before running out of fuel 3rd lap around Copse. 
So Q will be in the 29's.

The baseline setup is fine, you should be aiming for mid to low 32's, ideally 31's on Softs, before starting to fiddle with setup. I'm not entirely sure what to do with it myself, might put a few more clicks of wing so i can take Copse flat, might stiffen front springs and stiffen rear ARB. 
At the end I put on max wing front and rear to see what would happen, first lap was a 31.8 on mediums, (again all 50L fuel testing).

fyi - car has KERS so don't forget to use it. I use it on the 2 straights.