Various little nagging problems when trying to tune up a 3D printer

[neeboy74]

Hello to all:

I am trying to tune up a Stacker S2 3d printer using Simplify3D. It's a nice, good-size industrial machine and well-built, but it's giving me some nagging little issues:

1) Extrusion width. I am using I-Beam Impact PLA: 200 C Extruder, 100 C Bed. Filament sticks to bed great and lay-down appears to be good...but I've noticed that the first layer of the skirt is printing wider on the right side of the skirt than on the left.
2) Which way is best to control extrusion lay-down width? I've been changing the extrusion multiplier, but this sees like too arbitrary a way to fix my width issue.
3) I've been making small blocks/prints of buildings. I noticed when I took the parts off the bed that the edges show "sagging." I'm NOT saying the parts are lifting/curling up off the bed, that's actually one problem i'm NOT having AT ALL. It looks like the corners of the layers aren't lining up. And it's doing the EXACT same thing on two parts being printed in the same session, the edges of the layers are gradually bowing inwards, then back outwards, like what a rope-suspension bride looks like. The fact that i's doing the EXACT same thing on both parts suggests a parameter/software tweak of some sort is in order....
4) lots of stringing when trying to print multiple parts on the bed at once.

I've attached some pictures for reference. Thanks very much in advance for any help/advice!