plants showing signs of getting incorrect light

[Zyzzyzus]

Hello,

I have a Barbosella cogniauxania and a Stelis repens in a terrarium. I noticed yesterday that the Barbosella is turning purple in places, the way plants do when they get too much sun. The Stelis is looking a bit dark. It seems like the obvious solution is to switch them, but is that likely to be more traumatic than leaving them in places with less than ideal lighting? I am getting a couple more plants on Thursday, one which is definitely supposed to like more light than the Barbosella, so I could mount it in a way that shades the Barbosella. But that still wouldn't help the Stelis.

Thanks!