Whichever one you go with. I’d use distilled water so you don’t get mineral deposits all over the place. (White film)
I also wouldn’t put the humidifier inside that small space. Rather outside it, with extraction passively sucking in the humid air. This will make your RH more stable, than bouncing up & down when the fans are on.
I’m going on a water run tomorrow so I can chop my banana Kush down. RH here is about 40% inside the tent with a huge plant in there. So I’m going to need the humidifier in there with my fan blowing directly at it. I’m also going to run an intake from outside into the tent to keep temps in a nice range.