A list of popular paints and their levels of transparency and opaqueness.
Your don’t need to buy commercially available Flow Enhancers. Here is a link to a video by Painting-By-Numbers specialist Melanie B that shows you recipies for making your own Flow Enhancer.

Painting By Numbers: The Basics and Beyond is my new book on advanced painting by numbers techniques. Click here to go to your local Amazon web page (link now fixed) and read a sample, and buy a Kindle version (for a Kindle device or Kindle App) or a paperback version. If you are in Australia, New Zealand or Japan; you can buy the paperback HERE.