Context: So I drew some logos in black pen on paper and scanned them in order to make vector images. I traced the outlines (b&w) which worked great. My original, hand drawn lines look a bit shaky though, so I decided to smooth all the lines.
Problem: Now, my issue is that Illustrator does not seem know that all the fat black lines are meant to have the same thickness, so basically the surrounding paths are not "correlated" when I make changes.
Example: If I have, say, a circle, it has an inner path and an outer path, enclosing the fat black line I drew. When I smooth both the inside and outside path of the circle, the two lines are no longer completely parallel, i.e. the fat black line gets fatter and thinner.
In the case of a circle there are easy ways around that, but my logos have complex images of animals etc. The paths are all nice and smooth now but it just takes me ages to make sure that the fat outline that the two paths enclose has a consistent thickness everywhere.
Question: Is there a way to trace not the outline of the fat, drawn lines, but rather, the line itself? Or is there some other method I can use? I tried line art tracing, but half my lines went missing, so that was no good for me... Thanks! 
