Well, actually any size is possibile It's just that I use 16x16 since well, I guess since I just choose them to be 16x16 haha.
But well, I might use gigantic caves for the wrecked spaceship Or how about a 21th century city that has been burried under ground? For the theme of my server I could practicly use anything haha. Except for fluffy wool caves haha.
The bonus map rainbow cave XD Or I'll might make the crystal cave have alot of gold veins aswell
Anyway, anything is possibile
Like this would be a cave of 48 blocks wide:
There's even a way simpler metod to do this and make it look curvy and hopefully natural ( I might be experimenting with this idea )
How about making a couple of chasms, Filling them with wool, delete the surrounding stone and convert the wool to air. Then simply branch them! It would look kinda crazy I guess but it would be super easy to branch! Like what the heck just trow a couple of WeightedBranches in the config and see what happens I imagine there would be a HUGE cave system as result if you do it correctly with a bit of tweaking and experimenting
Seriously, this idea has potentional to be a breaktrouch for making caves