>>7767850
>brush do you use
one of the defaut csp brushes (real g-pen)
>how do you get that line weight
find some manga/doujin pages like picrel in original resolution (~7000x5000px) and trace it to get the feeling of the thing
and after studying them you apply them in your own work

here are some pages in original resolution(click download original)
https://exhentai.org/g/1903161/1c20b0dbb3/