I have a unique setup that includes a fishtank, so I dont have to account for run-off, but mine is on a forced system from the tank pump that rises to the top of the cage to a tube that forms an oval inside the ceiling of the cage. In this tube I have added 7 1/2 GPH drippers that, when active, "rain" inside the cage. I have moved some of the vines and leaves inside the cage to maximize the spread of the water, allowing multiple places for Gron to drink from.
We have been working on making a rain system and it just never comes out exactly as I want it to. I think we will prob just get the mist king rain set up or more nozzles. The drippers and misters from home depot just put out too much water, the mist is too heavy.