I've locked up with one face and a hair prop using 2 gigs ram... Your settings seem fine. But,,, most cannot render this many figures at once. Not in Poser, anyway. As mentioned but, differently.. you can render the back 2 figures (all else ivisible), save as a tiff. Import tiff as the new background. Make all visible, then the back 2 invisible, render. Using an image map on a one sided square is better still. Less artifacting. Armies have been rendered this way.