Hi Kairi,
Both of the external foggers will allow you to fill less frequently.
If you set your fogger up on a timer then you just have to determine how often you need it to fog and for how long to keep your humidity at the levels you need.

The waterfall/fogger system works well, but you will need to change the water often depending on what tree frogs you have and how dirty the water gets. If they get it dirty every night then the waterfall/fogger isn't for you.

Check out some of the videos on youtube and you'll see how the foggers work. One thing foggers do not do is water the plants ig your viv has live plants. A rain system will do this if that is what your looking also.

I believe many people here have worked with foggers so you will hopefully get some more answers as to what works well with what you have.