I'm having problems with thin walls where no infill is used.

smaller nozzle size setting in Slic3r. Used 0.4 instead of 0.5

Odd… The nozzle size should be set to the actual size really. If you put the setting lower than actual size it should just recalculate the material feed, giving you less flow… which could be accomplished by increasing filament diameter also… Not sure why this worked.

@Tim_Lathouwers setting the nozzle size lower would reduce separation path of the nozzle. You wouldn’t take the same path with a 0.35 nozzle as you would with a 0.5, you’d need to take more, because filament/extrudate wouldn’t take up as much space. It would not simply just recalculate how much material it put out. In order to completely infill a 2"x2" square with a 0.35mm nozzle, you’re going to have to travel a lot more.