I just done this after 2 days of trying.
I used the L750, medium tires.
I used fuel map 6 which can do about 10laps on a full tank
I pitted the end of lap 10 which was around 11 min in fully filled up and had new tires, stayed on map 6 then again at the end of lap 19 which was 23min fully filled up and new tires.
Now I did not need to fully fill up but get around 65% to take me to the end, but the extra I got mean I could use fuel map 2 to take me to the end.
With fuel map 6, you wont have the top end speed with the stock transmission so you will slowly be losing ground, but where this car excels at is corning, throw the car around those bends as quickly as possible.
But with fuel maps 3 and lower you will be gaining ground.
Now to get the most amount of laps per tank, I lifted off just before turn 2, so I did not have to use as much brake for turn 3 and could brake a little later. just before the right bend before turn 5 was another lift off point, before turn 6 and at the decent towards turn 10a
Take caution with the pit entry, you can easily cross the lines or go off pit road and get a penalty, same goes for pit exit.
If you cut a corner even a little, you will get punished before you can even give back an advantage and 1/2s in a Gr1 car is a huge amount.
I dont know what it is with this track but touch the grass even a little and you will be bounced to the moon.