I’ve gone with 5 gal bucket setups with House of Hydro mist makers - the single might look like a chinese job (they probably are) but it can easily fully humidify a 2x4.
On the single disc I only need to refill the 5 gallon every 4-5 days.
The cool thing about them is they make multi-head emitters: In my 4x8, I’m putting in a 3 disc - it’s spendy ($98) but will just crank it out. They go all the way up to 12-disc!