Remember Ameri-Girl? She made an appearance on a sketch blog I tried to do about three years ago. Anyway I had posted a page of sketches of her so I grabbed that image for a test. I set out to only use a standard stoke for my line width (like in the past) and then go and use that new line width tool to see how long it would take reworking all the lines... I would suggest using a Wacom tablet and the brush tool then adjusting with the line width tool.