There're 2 brush in this material set
The based one and the hard opacity version (that used on the thumbnail)
both are making line smaller than actually brush size , no brush texture used and had after-rendered watercolor effect.
So if they aren't suited you, you could adjust everything.
※I didn't recommend to use it for coloring because pen pressure aren't suited

The hard version
I use for second-sketching , doodling and line art when it's not full illustration works

Category 1
Update history
change pen pressure of brushes' size a little bit
(First time doing manage material catalogue and it becomes a mess so it can't be helped to upload again)