Just a ditto ... If you want to get 'more' help, do start a new thread.
Also, if you have a lot of walls to do, and you're doing them in a day, you can try spraying your 'solution' in a garden sprayer. But, if you're doing just a room, or even 2, I'd use a sponge for sure. Certainly, you an use a sponge for ANY number of rooms. Once I got a rhythm, I needed something faster than a sponge. (I did 3 bedrooms, a hallway, a stairway, 2 bathrooms, and a foyer, over 2 days.)