I had the same problem mate and im really anal like you so spent bloody hours shimming one side up to match the other.I used bolts to fix the fog in in(mine arnt dummy if it makes any difference)i used nylocs to secure them but varied the tightness on the bolts to get the desired flush fitting.
I guess another trick,although a bit of a pikey way to do it to pull them in flush in the middle where im guessing the problem lies is to get a tie wrap around the silver clip and get your bonce under the front bumper and attach it to the bumper iron pulling it till it is flush.
Like i said a pikey way to do it but it would do the job.