Discharge originally built the vanilla ender farm. Mort and myself helped to complete it. At this point i believe that the higher levels aren't actually spawning anything so yeah go ahead and widen it Mc, just be careful of the chests etc.
One thing I would suggest is it might we worth waiting until 1.8 when the endermite may make current ender farm designs obsolete. A highly efficient and much lower resource ender farm is now possible in the current snapshot (Assuming things haven't changed since I last checked).
This is true, however if you'd still like to try. You have permission to.
I may wait, sadly I tried to start, but then came to the stop of that there are so many layers to it...