You may also consider screening the entire sides for airflow. My main concern would be waterproofing all wood surfaces. I believe they use laminate over particle board for their solid panels, which will not last as long in a humid environment.
I looked at their cages in the past but felt...
You may also try rare earth magnets. They are very strong. Epoxy or glue one to the end of your vines or branches, place another one outside the glass.
I'm so sorry Carol to here about Romeo. I couldn't believe the post heading. He was my favorite Sambava of all here on the forum, such beautiful coloration. He will be missed not only by you but all who knew him.
He's probably frightened by your cham climbing on his cage. Is there a visual barrier between cages where they can't see each other? Your positioning of his cage in your cham room might suit you but if he is able to see other chams that may be enough to stress him and cause him to stay hidden.