To me it seems like this would be the most balanced way of playing 4-3-3 (as a system not with regards to who's starting or not, signings etc):
Welbeck-Rooney-Januzaj--
---Di Maria---Herrera------
--------Carrick------------
Shaw--Rojo-Jones--Rafael-
A touch more offensive version of how Liverpool started against City yesterday for instance. Of course, this would have us leave out two out of Rooney/RVP and Mata/Herrera which seems like a waste currently. But it seems like this would perfectly fit Di Maria as this has been how he's been used for Argentina and Real with Welbeck driving centrally like Messi / Ronaldo and him taking up the wide position on the left side. I would like another winger for this to work.
I don't really trust our midfield and defense to cope with playing gung-ho 4-3-3 like this, it doesn't look very balanced to me:
Di Maria-Rooney-Januzaj
---------Mata----------
-----Carrick-Herrera----
Shaw-Rojo-Jones-Rafael
Anyhow, it will be very very interesting to see where LVG plans to use Di Maria. He mentioned him once as being a top winger, but now mentioned him as a midfielder. Might just be a language thing though. But I would not be surprised if long term, if we're going 4-3-3 long term that he is looking to create the first formation in this post, rather than the second one.