You'd better practice according to Song Huizong's original post. The words are "thin" and easy to express with a pen. You just have to follow them carefully and write as much as possible. However, it takes hard work to practice hard pen calligraphy. If you can stand loneliness, start with regular script. It will take at least a year to make great progress.
In addition, I have to remind you that "thin golden body" is the font of national subjugation, and it is the font of "romantic", which has a kind of "enchanting beauty" and is easy to make people feel depressed unconsciously. It's ok to enjoy yourself in your spare time, and it's best not to practice! It is best to practice the calligraphy of Ou Yangxun, Liu Gongquan and Zhao Mengfu. Their style of writing is also easy to express with pen, and there is also a kind of "integrity" in their style of writing. However, it takes a lot of effort to express the style of "colorful body" with a pen, which is not easy for ordinary people to do.