While using AWN with a dual-head configuration (TwinView, nVidia), it is expected that maximized applications would fill the secondary display that AWN is not displayed on.
It appears that this can be traced to a line in awn_x_set_strut function. If I change the xutils_set_strut line to "...icon_offset, x, x + (width - 1));" then all applications maximized on my secondary display cover the entire screen, and applications maximized on the primary display do not cover the bar. Presumably this is because screen coords start at 0, so 1680 in my case would put it on the second desktop space.
Single head configurations work as expected with this change.
--- My apologies for the commenting from myself.
bug #147730 and bug #157714 could benefit from a struts rewrite, similar to gnome-panel's implementation.
Edit: tested changes on single head X. Worked as expected, maximized windows did not cover bar. Perhaps there's a flag for XChangeProperty that can be utilized.. width/2 seems like a bit of a hack.