Heya Devastation and welcome to the forums!

if you are going to 5 box... one thing to remember is to 'recruit-a-friend' from your main account. this will save you 1 months fee per new account.

and yes, your rig looks like it will run 5x wow... of course, all of your wow screens won't be 100 fps each, more like 15 background and 40 in the foreground while active.

if you have any questions on setting up, please feel free to drop me a note.