I have ran into the same problem. Lots of extra material around the part. Took me 2 days to figure out what was wrong. I was doing a 1mm wall, it put a .4mm perimeter on outside and inside then put a line in between. There is only .2mm gap and the nozzle is .4mm. If I manual make the width .5 then all is good. I think the system should be able to handle this correctly.by ccmn2000 - Slic3r