Yes you can get temperatures from a pretty good distance. I don't really go more that 3 feet away with mine. But i have taken accurate temps from up to 20 feet away. I bought mine on ebay and it works great...
I got 2 clutches of panthers right now and hopefully one will be hatching within the next month. Mistisos are so sick!.. I am hopefully getting a baby meller soon from someone on here. I gotta ask, on ur avatar pic is that cow eating bud? hahaha
Are you giving him calcium without d3 at all? You might wanna look at this.
https://www.chameleonforums.com/blogs/sandrachameleon/232-tongue-troubles.html
I have a couple cages that size and I have a misting system and you are going to need some sort of drainage. I have a couple racks in my room and I just drill holes on the bottom of the cage and connect funnels to them and run tubing from the funnels into a bucket. This might take a little while...