Tried my hardest to make a mock pen of the PaintTool Sai Brush, not pencil.

Change brush tip to simple circle brush if needed, highly recommended to match more with Sai brush, I just wanted something more oval.

Turn on stabilization and stabilization mode to "increase stabilization when drawing slowly" if you don't want shakey lines. I wanted them because I enjoy the natural feel.
Change brush tip to simple circle brush if needed, highly recommended to match more with Sai brush, I just wanted something more oval.
Can be used for color, sketch and lineart.
Make the pen pressure dot go all the way down to the pen pressure 100% mark to match more if you'd like. Brush is very simple, I just made things a bit to my preference in lines.