When I installed my BTG duals one side hung down lower then the other. I managed to bend the low side bracket to raise the hanger by placing the flat of the bracket across two crescent wrench handles about an inch or so apart and striking the middle with a hammer. Watch out for the "bonce back".
Bolt it on and test the fit. Bend it more as needed. If you bend it too far, lay it on the garage floor hump side up and hammer the bend down a little until it's just right.
I made my second lower fascia cut out exactly the same distance from the wheel well as the stock single one. I didn't have a problem with one side or the other sticking out more then the other but the right side (passenger) was not centered in the cut out. I solved this by sticking a length of pipe into the tip and applying a bit of leverage to swing it out a 1/2" or so. If I remember correctly, I may have put some blocks of wood between the axle and the corner bend back behind the spare to have something solid to leverage against. It's hard to describe but maybe you can get the idea.
Remember universal law #1: All mods have to be modified to work or fit.
