Dualiner storage

[Adturb]

Recently bought a 447 dualiner and after some ideas for storage in the back. It has comfort 1st row and all headlining and sides.

My current thought is a shelf (of sorts the same height as the folded seats with a couple of hinged sections to aid access and create a level platform and then secure the frame to the tie down rails.

Also does anyone know the there are any captive nuts for bulkheads, etc hiding behind any of the C pillar trims?

Thanks!