OK, I started fastening all these pieces together to prevent anything from flying up at me in the event of an accident. So far, it is all going as planned:

3/8" anchors:


There are covers for the bolts:


They are attached to these blocks that are attached to the false floor, using 3/8" bolts again:


Height of the bulkhead meets the bottom of the back seats perfectly:


Angle steel attached to the false floor for the small bulkhead:


With elongated holes to allow minor adjustments to the height of the small bulkhead to the top of the subwoofer boxes, the Line-X will affect the overall height.