If I were establishing a noise or aesthetic windbreak, I would probably select two different species of conifer; however, the choice is completely up to whomever is buying and planting the trees. You may also want to consider "Thuja Green Giant", northern white-cedar, and white fir.
Common within-row windbreak spacing varies between 6-18 feet; and between-row spacing varies between 8-20 feet. The reason for the variability is due to windbreak design and overall utility of said “windbreak”; species composition (mixture of shrubs, small conifers, large conifers, small hardwoods, large hardwoods, etc.); and number of rows (1, 2, or 3 row windbreak designs).
Ultimately, these decisions are up to you :-)