Just the pot... That said, my chameleon only free ranges while being supervised. So, the risk of an escape is minimal (in my opinion).
Best of luck with your free range setup.(y)
Horn worms are super squishy critters... So, I don't know which rule(s) of thumb apply. That said, Chameleons can eat pretty large Horn worms relative to their own their size (see picture below). I'd definitely start with some of the smaller ones then slowly work your way up in size.
NOTE...
Just curious, do any of you track the amount of food your Chameleons consume (by weight)? In case it isn't obvious already... Yes, I recently acquired gram scale and now feel compelled to weigh EVERYTHING! ;)
Coincidentally, I've also been experimenting with Lobster roaches (as feeders). My...