I think the problem is it is only making one display, i see all these examples of exporting DISPLAY=:0 to get to miner to work or exporting DISPLAY=:0.1 to get access to a different display. However my setup seems to only have one display 0.0, I dont have to export for the miners to work and I can't switch to any other one.
You could try changing:
Screen "aticonfig-Screen[1]-0" LeftOf "aticonfig-Screen[0]-0"
to
Screen 1 "aticonfig-Screen[1]-0" LeftOf "aticonfig-Screen[0]-0"
It should force your second screen to be identified as :0.1
What's the output of "xdpyinfo -ext XINERAMA | grep head" now?
Openbox needs the screen geometry to be exported in the XINERAMA extension's protocol for the maximize on one screen thing to work. RandR provides this functionality, which is why I suggested turning it on. When the command above doesn't show anything, that suggests that there's no Xinerama information available.