We did a faux finish in our studio. But we just did a simple sponge painting. People always think it's wallpaper when they see it. And we did it on the entire wall, not just the top. I used one size sponge and Bruce followed behind me with a different size sponge.
We also used Behr from Home Depot! I'm sure you'll do fine with it. And I hope you'll share pictures of it when you are finished.
The good thing about most of these faux techniques is that it's hard to mess them up.