I'm actually quite new to LFS, only had it for a few months or so.... I have, however, been driving simulated endruance races for almost three years now
Endurance setups are really relying on your tire/fuel economy and your driving, like stated above.
I try to setup so that the inner two temp values on a tire are equal and try to balance the car so it burns the tires equal front and rear, at least on the "outside".
It does take a little tweaking, and it's not a very fast setup, and in general you will have to be a little carefull the first lap until the tires has reached a driveable temp. In return you get tires that last long, and you can probably save up to one pitstop in any 3 hour event.
Oh and to get away with this, you really have be a stable driver and drive every lap almost the same