How to choose a pen for practicing Yan Zhenqing's regular script, and what kind of brush is the best?

Yan-style strokes are plump, rigorous in structure, grand in overall momentum, vigorous and dense, vigorous and powerful. Wool brush with thick writing head, short pen tip and good ink storage ability should be the best choice, but beginners should choose sheep with two brushes, pure wool brush is too soft to master, and beginners should choose sheep with two brushes.