I got these wrought iron plant stands at Lowes and was able to raise my Sheffelera's up much higher in the cage. You can do it but turning another plant pot upside down too. That will help with some of the plant coverage in the top as well. NOt sure how big your enclosure is but a 5 gallon bucket would work too if the enclosure is tall enough. I think my stands are 17" tall, but I also have really big plants in 48" tall enclosures.
I agree more horizontal and vertical climbing branches. If you are getting dowels I think its a good idea to get some of varying diameters too so his feet are changing and getting different exercise. I bought a few bunches of curly willow branches and use those in my spaces as well. They guys seem to love them particularly climbing them vertically. I have a few that they can be right at the top of the enclosures (not right under lights). They seem to like that being on top of the world feeling.
He is awesome looking and I just love the out of the bag shot.
If you are like me your enclosures will always be a work in progress, plants grow, chams grow, I like to move stuff around now and then so they don't get too bored. Have fun with it, but remember its his house so make sure he has lots of places to hide if he doesn't wish to be seen.