How do I replace non-popcorn ceiling texture?

I had a really terrible idea that I was going to remove the ceiling texture in my home and go with a smooth ceiling. This turned out to be much more difficult than I had anticipated.
All the videos online showed removing popcorn to be easy, but this is not popcorn.
I have decided not to go through with this, but now I have a 3' x 5' area of my ceiling that is scraped flat and dry-wall is visible. I need to reproduce the texture in the photo shown. I'm pretty sure that I found the brush needed from Amazon: here. I also looked for paint used in the texturing process, but all I found was a powder mix which you add to the paint to thicken it.
It was all white and so it wasn't noticeable but there are tiny Styrofoam bits in the powder (popcorn) and it didn't get the paint thick enough to do the job, and the Styrofoam totally screwed up the texture.
Ultimately, I had watery paint slopping off the ceiling with bumps all over it and it was a total disaster all over again.
I now need to scrape THAT off and try again and I need to know what I should be doing/using to get this texture (or something close).

http://imgur.com/a/js0ef

Questions:

• What type of paint (or is it even paint) should I be using to texture the ceiling?
• Should I use a mix-in? And how much to prevent the paint from dripping all over the floor?
• Is the brush linked the right tool for the job? It seemed close, but considering everything else about the project was going wrong it's hard to tell.