Pencils are better, pens are a little slippery. In addition, there is a video of Tian on verycd, so you can look at all the pens that need to be written back. After watching the video, you will understand that it does not depend entirely on the change of pen thickness.
It has nothing to do with pens. The pen used in Tian Yingzhang's video is Yongsheng 10 1. 100 yuan