Drainage is a must, especially for Jackson's. A hole at the bottom, covered with screen would be acceptable. However and all screen enclosure is optimal.
Amazon has a packaged deal for a 18x18x30 reptibreeze enclosure combined with a reptisun 2 lamp terrarium hood for roughly $95.ºº w/shipping included. Saved me about $60 compared to buying it at retail price from local pet suppliers.
I use an all screen enclosure atop a
white plastic ventilated storage shelving unit ->
http://www.homedepot.com/p/HDX-4-Shelf-18-in-D-x-36-in-W-x-55-in-H-Black-Plastic-Ventilated-Storage-Shelving-Unit-17601102/202504715#.Ugc0zRY1FSU and drainage is no longer an issue.
I hardly ever see my baby drinking, she is normally pretty shy unless I have crickets or a lid full of fruit flies in my hand. Seeing as you have a dripper it is likely that your cham was drinking while you are away rather than sickness or anything like that.
The advice you mentioned about not having waterfalls or standing water is valid for a number of reasons.
Standing water does make for an appealing place for insects to die, chameleons to poop and bacteria to flourish. If the crickets were to drink from the mcnastyness growing in that week old water dish, and then hop along to be eaten by your cham... Im sure you know where im going with that...
Keeping a bowl at the bottom to catch excess water is perfectly fine, as long as you keep it clean.
Chameleons are not attracted to standing water anyhow and misting by hand is often stressful. No matter what you do the physics behind the mechanics of the mister make sure that the water coming out is always cold no matter how hot it is in the bottle. If you wouldn't drink it or submerse yourself with the same water then the chances are your chameleon can get sick from it.
Meanwhile in nature, far far from home... the light reflecting off of the moving droplets of morning dew, misty mountain clouds and or rainfall trigger an instinct to drink.
For some chams it could take a number of minutes of heavy rain like misting before they react and are compelled to drink.
Once he is conditioned to your hand coming in and giving water, his instinct will eventually adapt his reaction to the series of sounds you make coming into the room and the sight of your hand coming near the enclosure.
Although I personally feel that the behavior you mentioned is caused by dehydration and thirst as apposed to recognition and affection.
Be attentive to your chams activity during the day. Watch whether he spends most of his time basking or chilling out. Observe his movement while hunting and watch for clumsiness. The strength of his grip as he moves as wells as the various speeds at which he moves for different reasons are very important.
The level of alertness shown when you interact with him and as he interacts with is environment. The urate and feces are very informational...
These are all GREAT indicators of whats going on inside of them but without a vet we cant really do much when problems come up.
Preparation, observation, research and adaptation of your husbandry practices are really the only things we can do to help them be healthy.
Google is great and a simple keyword search can and will save you a lot of time and patience.
for example;
if the urates, (the white things attached to the poop) are not completely white, than your cham is probably dehydrated.
Hope this helps
No problems, just solutions.