glad you found out how to slow cook.. I just got the reminder of boiled corn-on-the-cob too.. YUK.
Definately pull the membrane off the back. Take a butter knife and run it under the membrane, along one of the ribs, in the middle of the rack. You can then run a finger along that rib and grasp the membrane and pull it off from the middle out. There's a you tube video somewhere but I'm too tired and lazy to find it and link it.