You'll do fine with the basic for a single cage (or three). I use two basic kits to run 6 cages (10 nozzles each kit). If you plan to add more cages you might want to bump up, but only necessary if you go over 10 nozzles.
I have 2 24x24x48 cages and the dual nozzle isn't enough for my taste. I'll be adding a 3rd, if not a 4th nozzle next week. Also, if you plan to mount the nozzles outside the cage instead of inside (some do this for a rain-like effect), you can get the green house nozzles instead, which are a few bucks cheaper. Or you can go with an off brand. The nozzles are expensive!!
I have come to find the same. 1 nozzle from what I have read, is said to cover up to a 14x14 area, with some fringe mist extending to 16inches or so. I chalked it up to 12inch areas, for actual full on mist.
My 24x48x48 (actually taller, but thats soil to screen bio), I had setup using 4 nozzles in the front, 1 for every foot. Not enough.
The front of the cage, is fine, its great, the plants get adequate water, ect the back gets nothing. I lost 2 rare expensive plants due to this

, a 35 dollar orchid and a 75 dollar tassel fern

. There is now 2 more nozzles in the back, through the screen, even that isnt enough, I have 2 Tublar Sword ferns in the back of the Viv, floor level planted I have to manually water, they dont get nearly enough. I only did 2, because those are mounted through the screen, which I need to fix soon and then will have 4.
TLDR, I would personally suggest everyone follows my new found 12inch rule, in all enclosures. Look at your cage/viv from a birdeyes eye view, and place nozzles for each 12x12 section.
One of those options for a 24x24, and on odd sizes error to more nozzles than less, so a 30x24xX I would do a 6 nozzle spread. Also take into account the spreads, ESPECIALLY with Epiphytes!
These nozzles, are meant single nozzle for a 18x18 exoterra, with 2 inch walls and background, leaving a 14x14 area, 1 nozzle covers that perfectly, a 24x24 cham cage not so much.
Probably not as big of a deal with potted plants, I am not sure. However if you have a bio with bare root Epiphytes its a HUGE deal.