I spaced mine at 3'' on my mega tree and they look great. my roof line, windows, doors, and siding outline are all factory spaced at 3 3/4-4'' and they look fine. I used a uni-bit to drill all my holes into 1/2'' pvc for my mega tree, it cut threw a lot easier than a drill bit. if your doing a matrix, I would probably space them a little closer.