For most of my 30+ years of keeping chameleons I've used glass cages and I don't think I've had any chameleon develop an RI....it's all in the way you keep the cages set up... IMHO.
I am a Canadian here too. I had this struggle I used to have a screen and now I have a glass. The glass kept the humid and temp up very well. And it look much better too I think you should get a glass cage