Weight and temperature are certainly factors, as is utilisation. Correct on all counts.
Longish days certainly but easy enough as only 2 sectors - all the hard work is on the ground. Days just as long occur with 4 sectors and are far more debilitating. Try a double Nice for instance.
Sharm or the Canaries are quite a bit longer. (Sharm is illegally long unless you gat a piece of paper from the CAA to say it isn't)