The way I do the outlines is to use the pencil tool to draw the lines. I then move the anchor points around to tweak the line shape. Once I get them to my linking, I then add several stroke weights. The paths are then converted to shapes and then the endpoints are joined together. That is how I get my thicks and thins. It is very time consuming. I have been experimenting with the brush tool to see if I can get the similar results but haven't come up with anything I like. The search continues.