Tian Yingzhang has also studied Ou Kai, so learning books should be based on the source.
Personally, I suggest learning regular script from Ou Yangxun. Representative posts include: Jiucheng Palace Ritual Spring inscription, but European style is more rigorous. If personal control is not good, it is easy to write more and more tightly and can't relax.
Duobao Monument in Yan Zhenqing. Zhao Mengfu's will do.
If you want to turn to regular script, I recommend a person here: Chu Suiliang, who has Preface to the Sermon of Yanta and Yin Fujing.
Chu used a smart and elegant pen, and his brushwork inherited Wei and Jin Dynasties. It is helpful for the development of regular script and running script in the future.
Another point is never to buy Mi Zige's books, and try to be loyal to the original.
The words of one family are not necessarily enough ~! I hope I can help you!