I've used the fire and ice spot lights (in blue only and a combo of blue and green)...gives off a nice water like effect...there is also clear if you don't want a color per say, and it gives the same reflective look.
This is early morning, mix of blue/green fire and ice spots
This is night time, blue fire and ice only
Depending how far from the wall you put it, they will cover a very large area. I can get the entire front of my house with 2-3. You could probably get your 10x12 ft area with 1-2