I like the tube enclosures because i can use thicker non window screen, with bigger holes.
I use the 4ft tall version of this 1/2 inch hardware cloth:
https://www.amazon.com/Origin-Point-272405-Hardware-24-Inch/dp/B000HHSCLA/ref=sr_1_14?ie=UTF8&qid=1505498136&sr=8-14&keywords=hardware+cloth+1/2+inch
It hardly blocks any light from the florescent tubes, and the cham has no problem climbing all over it. As a bonus you can tong feed feeders through the mesh. The only down side to the large opening is you can free range feeders, cup or hand feeding only.
So i just get that vinyl coated hardware cloth, a washing machine drip tray, and some potted plants, and im done.
Like i said the only engineering/hard part, is coming up with a door opening based on what latches/hinges you have available.
You can google image search alot of variants of this design.