I want to learn regular script hard pen calligraphy, whose works are easier to copy?

Don't copy Pang Zhonghua's, his handwriting is scattered, which is not suitable for beginners.

You can take a look at the earliest version of the standard course of hard-pen regular script, about ten years ago. A new edition is now available, soliciting works of members of Beijing Calligraphy Association. I started studying in the third grade of primary school. What impressed me most was Mr. Zhao Houxiang's works, which were vigorous and full of China traditional charm. You can choose this book if you have time and interest.