Nothing I have found works easily. This is a deficiency with the AOZ kit. We have it in two cars. One car I fabricated brackets. The other I took a standard double DIN cage, shimmed it it pine wood (mixing sticks, actually), and ran screws through the cage and the shims to get the cage centered properly and secure. Both methods wound up working. The whole thing would have been 100x sinplere if AOZ had made a flange part of the plastic piece.