Halfway between the king and center pin on the opposite side of where you normally drill. That way, you have an easy shot at the field, a small chance at a field/baseline double, and you still leave the baselines standing on your basket side for possible field/baseline doubles later in the game.
In my opinion, while 4 meter drills are fairly accurate for a well-practiced inkastare, an 8 meter drill is risky at best. One small mound of dirt could send the throw left or right and not give you any chance at a double as well as taking away the "easy" field throw.