Wouldnt the shade from the plants keep the rootzone in an acceptable level?
Reason I ask, in my particular set up, its an aero stadium as you know D, the temps in the room are steady at 83F during the summer. Its a basic fence post design and I havent had problems with high temps around the rootzone.
The bucket might be shielded from radiant heat, but it's still subject to the air temperature, and heat rises.... Chill the water, or get some coco. This is a problem i had never even considered... when I was thinking about fitting the bobbleracks with buckets. Good thing I chose coco... Just gotta keep the bugs in check...