I come from many generations of cabinetmakers and furniture makers. The most useful advice I've been given from my late grandfather was "hang it and bang it". Be it off square walls, uneven floors or even maker error, sometimes you just need to put it up and make adjustments on the fly to make the most appealing result.

The hinges will certainly buy you some flexibility, and if they're good hinges, you will be able to make some adjustments. It may not be perfectly level or square, but in finishing, visual trumps objective measurements for most things.

It's hard to give more advice than that without pictures of what the installation looks like (may be options for fill strips, trim pieces, etc).