Something more like 0.5 to 1.5A might be better for that servo, given its high torque.
You can calculate theoretical load currents from the other specifications for a DC motor (geared or not). current x voltage = power, torque x angular velocity = power.
Thus current = torque x angular velocity / voltage.
Here torque at 6V = 56 in.lb = 0.41 Nm - the max torque figure, roughly represents stall or near-stall condition
angular velocity at 6V = 5.5 rad/s (0.19s for 60 degrees).
Therefore theoretical current at that torque is 0.41 x 5.5 / 6.0 = 0.38A not allowing for any electrical or frictional losses. 1A is a good
guestimate I think.