Before I bought my prop balancer, I simply used a mechanical pencil that had the right size point that fit the props. The DJI props all showed perfect balance but the carbon fiber props had exactly half of them out of balance, by a lot. Then I got smart and bought the Duo-Bro balancer from Amazon.com and again, it showed the same. So, I got the exact same results with either method but since I bought it, I use the Du-Bro one. I have not found a single DJI prop to be out of balance, none!
Thanks,
Jim
WA5TEF