Paint Tool SAI - Flexible Brush settings

Line-art has been a difficult area for me.  I've been stubborn about painting/drawing with single size media, and while it works very comfortable when I'm drawing traditionally with a ballpoint pen (I just found a pair of Zebra's at Staples, one of my favourite barrels), the results on non-cintiq tablets are disappointing.

I'm going to try and break down my findings from Paint Tool SAI.