I can imagine how this can be a problem. Thin lines than in your original render have 1 pixel width, will be removed or suffer a strong
you misunderstood. In the original SVG there are no thin lines. The thin line was introduced/inserted by buggy down-rendering to the wanted size. (There are coincident lines in the SVG).
antialias wen reduced down. Re-rendering a image on a smaller resolution will result on a pixel perfect image (except thick eyebrows), where 1 pixel width is still 1 pixel.
Also the double drawing would be mostly irrelvant, if first render to the original given SVG size. It seems many problems are only introduced artifically by this toughtless(?) rendering-philosophy of RSVG (or Imakemagic), IMHO. :-/
...and the situation is even more complex than that. So more things that thing can go wrong.
Surely
Achim