Selecting suitable Dynamixel servo for my robotic project

Hello,
I have a robotic project, and in this project I have some joints , and I should take servo motor on each joint.
After I calculated torque of each joint, I found that my major joint needs 2.5 N/M torque.
If I wanna use Dynamixel Servo motor for that joint, which servo motor do you recommend for my major joint?

(In addition, The Dynamixel site (robotis.com), recommends using a servo motor whose torque you need is 20% of the stall torque of that servo motor.) can you help me about this recommendation in robotis.com ?