That's a quick test I did with Ben Nye Magicake Aqua Paints. It's water activated but I got it to look very opaque in just one layer (and they're fairly cheap). To get it to look thick, I first primer'd my face with a light concealer, and I used a medium sized make up brush to mix up the paints in their cases until I got the shade I wanted. use a LOT of water for this, because you really want to mix that paint up (and it'll dry later so don't worry). Before putting it on your skin, let the paint dry a bit because this makes it thicker. Once it's thicker, you get this even layer of paint that looks really good.
I hope this helps with your decision!