Use 3 parts glaze to 1 part paint to get a more subdued natural look to each color of paint that you use. This will give you slower drying time so you will be able to work with the paint better before it starts to dry. Do 3'x3' sections at a time. Use a "Sea" sponge for a more dramatic and natural blended look. Keep a bucket of water handy to rinse excess paint out of the sponge every so often. Sounds like a beautiful idea! If cost is a factor, You can purchase a gallon of glaze at Wal-mart for half the price of paint stores and it works just as well. I buy my paint at Home Depot or Lowes though.