Help! Who and where do I hire to figure out background dimensions?

I'm producing an animation that's more complicated than the style we've used in the past.

This one involves a constant zoom out, dynamic camera movement, vector images instead of raster like we've usually done.

I can't figure out on my own what shape/perspective and dimension/size of backgrounds to assign my background artist... Who might I search for to join our team and do this task?

And any recommendations for good places to find them? :O