From the looks of your picture it appears that one pack is behind the other. You would need less supporting structure if they were side by side or one on top of the other. I have mine side to side with 1/4 inch balsa pieces glued between them to provide an air gap. A piece of 3mm carbon fiber/honycomg material provides the front support and the landing gear mounts support the rear. 2 pieces of balsa fiberglass composite glued to the bottom of the packs align the packs on the gear mount and prevent the packs from moving once they are snugged down with velcro. I use velcro cinch straps which I cut down in width and length to make them lighter. They provide a very tight mounting. Changing the position of the balsa fiberglass laminate sticks (actually I added a third) allows me to shift the CG.

Not sure if any of this helps you but some pictures are at http://www.rcuniverse.com/forum/m_41..._4/key_/tm.htm near the bottom third of the page.

Good luck,
Stuart