No matter where you push on the back plate at this point, the ram carriage as well as the wedges used to keep the ram in place will be protected from any kind of pressure. With out disturbing their arrangement, place the back cover on, put screws back in place, turn on. They do need to be thick enough to be held in place when you put the back cover on. Don't lay them on any component/capacitors, You'll have room.
Lay one spacer right on the logic board parallel to the rear side of the ram carriage, and the other on the board perpendicular to the first. Next, get two pieces of spacer (I used a thin gauged bamboo knitting needle cut into two pieces no longer than the width of outside edges of the ram slot carriage.) Your spacers need to be non conductive, they need to be thicker than the rim of the ram carriage from board to top of carriage, but not so thick that they cause your back panel to warp. Wedge both sticks of ram in their slots with a shim in-between the ram and the battery housing.
