For cursive script, it is not necessarily the goat hair. The weasel hair and other hair types are used very much for cursive script brushes too. The function of a specific brush is related to the hair length, hair grade, etc. If you are changing to semi-cursive at the moment, we have 4 recommendation. We do not recommend you to buy the most professional type of brushes which are made with expensive materials because these brushes might be more suitable after you have mastered cursive scripts. Therefore, our recommendations are,
https://www.inkston.com/index.php?s=semi+cursive (These brushes are good options because the quality is professional level while they are not difficult to control compared to some professional brushes.)
Also, you can consider this 0503M brush. It is designed specially for landscape painting, semi-cursive script and cursive script. https://www.inkston.com/shop/brushes/inkston-calligraphy-landscape-brush/
For cursive script, especially the cursive style from Tang and Song dynasty, these two are good options,
Inkston 0801SW 豹狼毫 Bao Lang Hao Large Leopard Wolf Brush (Squirrel/Weasel)
hmmm, you can also consider trying a set of brushes for this transition to cursive script because the set has different sizes available. The most suitable set is this one, https://www.inkston.com/shop/brushes/red-star-jian-hao-wolf-wool-combination-brush-set/
All these brushes listed above have different shapes and materials. They all have different ‘personalities’. 🙂 I hope you can find the most suitable brushes which can allow you make the most of calligraphy joy.