There is a lot of disagreement about how much orange is ok vs how much is not. My approach is always to use an integrated approach—monitoring urates, and behavior. Running a test misting every so often can be helpful.
If I remember correctly @nightanole had the genius idea to add an extra misting nozzle to a small reservoir above the cage. The reservoir is dotted with a drip line. This way, when ever it mists, it adds water to the reservoir, which subsequently drips on whichever plants you run a drip line to.
With folks springing for solarmeters left, right and center, it’s worthwhile considering a considerably cheaper Par meter for our foliar friends. I have found that a decent light meter for measuring PAR is as useful for our plants, as the solar meter is for our chams.
For larger, more natural ponds—where epdm would be too expensive/not practical—montmorilite clay powder is applied to the excavated area. Once water is added, the clay forms a watertight barrier. It’s a favourite practice of cattle farmers for watering dug-outs.
There is some lively and thought provoking discussion about this topic. I highly recommend looking into the various facets of chameleon hydration. Warning: it can be a bit of a quagmire! But the evidence and data on all sides are well worth learning.