I had a really hard time inking with Photoshop. I have a wacom Intuos 4 large tablet. It is especially difficult to do the longer compound curves and ellipses. Not sure how you get such smooth curves Matt. What graphics tablet are you using? I ended up having to use Illustrator to do the drawing using the brush tool. Brushes can be changed to similar effect as photoshop. I did one with a paper bleed effect that I kind of like that I found on the internet. I am working on turning some of Kyle's brushes into vector brushes to get a similar effect.
Reference photo of my son's race car. Not sure why it imported upside down.
I found sketching in photoshop a little difficult though doable. Getting a nice inking was just not happening.