The original mounts have a load of movement in them so you can just push them by hand and make them line up before screwing the bolt down.

The powerflex ones dont have any give by hand, I had to leave the opposite side screwed in by 7-8 turns then had to loosen off the 4 bolts on the diff mount to drop the beam more and give a bit more room.

Then when it's all lined up torque them up ( off memory they're tight 70-90nm)