It is good practice to set the combat sight/GAS before battle begins to the distance to be expected by the map, or to set it at 1200-1800m. SABOTs have not that steep a flightpath than HEAT, and when I preset mostly 1500m, I use to fire at targets heading at me without lasing and leading at all. I may set the laser at that distance, too, before battle begins, and maybe will not ladse again any target as long as sights tell me (by experience) that they are rpoughly in the "envelope range" of 1500-2000 m. I often lase only at targets at greater distances, or if they are not staitonary or move not directly at my position or away from it. I also tend to prefer SABOT-heavy loadouts in my tanks, too, like the Germans prefer for their Leopards in reality as well.
Getting off one's own shot first definitely is an advantage.
In defensive position, I also often use the GAS as default, too, it gives me a more reliable visual estimation of whether the gun really can clear any terrain - like the rim of my own cover. The doghouse on top of the turret may clear an obstacle that the lower positioned gun does not. Plus it keeps you in training regarding using GAS.
Heck, I am, for some reason, do not play it that often anymore currently, but Yessir, I still love it.