There is no magical formula; it all depends of your imagination. However, it is advisable to install the light projector at a distance of 25 to 35 feet and you might consider getting a second one if you want a special effect. To learn about it check our laser light reviews.
Depending of your particular setting, such as existing street lights, the actual size of the house and the way you want the final set-up to look like, you could try putting one of them further away for a diluted effect. Experiment with the lights until you get the dream lighting you aim for and eventually share your masterpiece.