Brainstorming Help: - Flexible Solar Panel Install on RV Roof

About to put three 150 Watt semi-flexible solar panels on the fiberglass (FRP) roof of our 24' RV.

Each panels measure about 52" by 26.5" and weights about 8 pounds out of the box.
(Thanks largely to a number of folks here, the rest of the system is now on order and hopefully arriving late this week)

Some criteria I'm looking to meet:

Panels will be 'permanently' mounted (glued) to a backing which is:

• thermally conductive - to allow for cooling
• has minimal thermal expansion
• is rigid enough to support panels without significant deflection (i.e. flutter) when driving
• is lightweight
• reasonably cost effective.

I would like to mount them using bracketing which will give me:

• approx. 1" to 1.5" standoff - for airflow under to cool panel
• allow for tilt adjustment
• allow the panel to be removed relatively easily.

For the backing, I am currently considering:

• aluminum plate in the 1/8" (.120-.125) thickness range - possibly with stiffeners.
• aluminum honeycomb in the 1/2" thickness range

What would you use? Ideas would be greatly appreciated!