As mentioned in a previous post, I’m going to carry my track tires where the back seat normally goes.  Pulling the rear seat leaves a big pass through opening to the trunk.  I’ve got the battery back there and will soon add a rear-end catch-can/breather tank.  So, I needed to create a block off plate.  Used .025 aluminum sheet.  I didn’t have one piece that was big enough so I created two halves and still needed a center panel to get the width I needed.  Picture below shows it being held in place temporarily with clecos.  I’ll pull it back out, run a bead of body seam sealer around the perimeter and then rivet it in place.