I have a similar setup, but i have a separate player unit frame (and minimap) off screen that is sized for display on the main's via fx.

So on your setup my screens would be like below, i have 2 and 4 wider than what is displayed and that wider section is 'under' 3 and 5, 4 and 5 are wider than displayed and the wider section is 'under' 1. this allows me to show the images that are proportional to 1, but horribly unappealing on their own screen. the 'wider' parts are in a view port as well so there isnt issues with background terrain and so forth.

[2][3][1]
[4][5]

for what its worth i also have '1' carrying over to the another monitor and a view port that limits '1'. one this other monitor are where skada, quest, broker, combat log stuff are located.

the slaves just run, sexycooldown, buffbar, suf that is very grid-like and their casting bar that is visible. the vuhdo stuff is in that viewport that is tucked under the screen.