Hello, we are constructing a building and we mounted 4x4 boxes for the exterior lighting fixtures. They are mounted on the studs and are flush with the exterior sheathing. They plan to side the building with steel. The siding will be flat but will have a raised groove. I am sure that when the siding goes over my boxes there will be some that will have this raised groove in line with them and my fixture won't be flush. What is the best way to mount the fixture in this situation? Should I mount the fixtures and have the guys doing the siding go around them? Any help would be appreciated and I know people here have run into this before. Thanks!