Hi,
I was thinking about further tweaking the Slic3r settings, and have a few ideas for things you might try.
PLA is very particular about print temperatures. Set it as low as you can reliably extrude. Sometimes this can be as low as 160. For 0.3mm layers, 175 might be a good start.
Also, the reversal speed needs to be as high as you can manage. I remember the extrusion restarting a bit late, so boosting the extra distance after reversal to 0.1 might help. Also, find out how fast the printer can go, and set the infill speeds to a bit less than that.
With that in mind, I've created a configuration file (
http://tinyworkshop.org/ul/ORDBot.INI) which you might consider trying out. I'm curious to see how it works.