I love this! It really makes me want to get out my acrylics which I bought ages ago and do something with them... I have the problem though of fearing to waste paint, not least because it is quite expensive here.
May I ask how much you charged for the commission? And what are the dimensions of the canvases?
I get what you are saying regarding the cost of paint. You do waste a lot of it when you do a dirty pour. As for the size of the canvases, they were 40 x 11 inches (100 x 30 cm). I charged only for the materials because it was for a friend.