I can't tell from the pictures if the face of the cubby is flush with the dash or set back some. What is the set back? Also, is it only mounted by the front edge flange or are there flanges along the sides also?

The cubby is flush with the under side of the dash. If you look close the dash comes down then has a bend then another bend. The cubby sits flush with the last bend. The install in the photo has carpet with padding so the cubby goes from the carpet to the underside of the dash with not gap. Results may vary : ).