As Carol stated, none is best. You'll find it can get pretty messy and fecal batter can build up and worse if it gets wet. Its best to just use a sheet or 2 of paper towel and swap it out every other day or so. Considering a roll of Bounty is about $5 and will last about 2 months isn't too bad.
She may be drinking , you just don't see/catch her.
Just monitor her poop and make sure her urate (the white part) remains white. If it begins to show yellow/orange , this is a sign that she is not drinking.
~Jon
I was told by a reputable breeder that weight and conditioning plays a more significant role when it comes to females. 80g seems to be the magic number . That being said, most females are around 8-10+ months before they hit 80 grams .
-Jon
I'd also agree with Carol. Temps may be playing a roll. My Panthers would tend to be more dark during the winter months when the ambient temps were a lot cooler. During the warmer summer months they were considerably brighter.
~Jon
She looks good. I'm glad that you understand that she will lay eggs regardless of being mated or not. She doesn't look gravid in the pic you posted, but are you offering her a laying bin?
Also, Veiled Chameleons seem to be viv/cage territorial. They tend to be a bit more aggress and sport...
That being said. This seems to be getting good reviews. I like the fact that it's contained and filtered. If kept high enough to avoid feeders falling in and regular cleaning, this should make cham hydration pretty "easy". https://www.chameleonforums.com/water-fountain-does-work-small-chams-138632/
Understood, but a Cham is not a desert reptile like a Beardie or Monitor. Its skin will eventually ware at the contact points. The owner mentioned that as the weather gets warmer this will become a common practice.