With a rheostat you can simply increase or decrease the temperature. They make digital programmable switches that can control heat output with a thermometer, you can set the min and max.
If it's for night time temps, don't use a bulb that makes visible light. Even if it's red, blue, or...
The fridge will kill them. They aren't like meal worms. You have to keep them slightly moist too. If they dry out before you use them, they'll perish. I get them from Timberline, their trade mark is "Calciworms".
Offer him dark leafy greens, Kale, collard, mustard, dandelion, beet greens. My chameleons eat any living green I offer them. I can't keep pothos in there because they eat it within minutes.
Also the vertical axis would remain 16", if it's an arborial species - would appreciate more height than width/length. I sound kinda harsh, not trying to be, just critical thinking out loud.
I fail to see the reason as to why you would mutilate two enclosures to make one. If you do proceed, just make sure feeders don't have access to crevices or any gaps made by joining two cages together.
I'm all about innovation, but this seems futile or backwards. Two unmolested cages are...
Oh buddy! That enclosure you have is a palace and a half!!
Your Cham will have a hard time reliably finding food in there, being that young.
Best put a shallow dish in and put it where the vines are trellised down. Your Cham will see the movement and will gradually go for it. Nothing good...
They are pretty much like a Jackson's, if you are familiar. The questions is how fast do you want to burn the female out?
The male will breed, no matter the "season". The female needs to recoup after having a litter, that could be a few weeks if you are trying to produce many babies quickly...
Is it time to repot them? Sometimes it does more harm than good to prematurely repot a plant. Do you think it may be worth it to see how they react under your lights for a month or two before totally shocking them?
I don't have your answer specifically. I just posed a different question. I'd...
Try both and see what they go for. I personally like to cup feed my Chams, it's not as messy and I can quickly see if they need food with out trying to count roaming crickets/bugs.
A couple of mine refuse to cup feed. The rest don't mind at all.