i don't have the same lift as you. when i did mine a jacked up the rear end and then put a chain from the rack to a tree branch. then slowly lowered the jack down letting the branch and rack support the bike. took the jack and put pressure under the rear end and undid both of my shocks. lowered the jack a little, so i could put the brackets on.
hope you can understand that. just ask if you can't
hope you can understand that. just ask if you can't