I dont have a chance to check specifics but if theres no way to do it using the gui you can try the xrandr command. it has lots of options for screen positioning and the like.
funny how peoples experience differs. Been using linux for years, and never had something break in a major way. I understand your point but would encourage you to try again someday.
windows were never meant to overlap, the desktop was never meant to be looked at. do not fear the real tiling window manager. sooner or later, you'll make the switch.
I dont have a chance to check specifics but if theres no way to do it using the gui you can try the xrandr command. it has lots of options for screen positioning and the like.