A: You mentioned Red Tip Photinia but as you have noticed many nurseries have stopped stocking them because they can contract a serious disease called fire blight. However, we have several other plants that grow quite tall and should provide you with a good screen cover. Think about wax myrtle, viburnum or pittosporum.
Southern wax myrtle, Myrica cerifera, takes a variety of soils, grows in full to partial sun and can reach heights 12-15 feet. Plant should be placed 10 feet apart, watered well at establishment but will then need no further care. Wax myrtle is moderately drought tolerant but can tolerate salt spray. It may have an occasional worm defoliate leaves but those can be easily pruned out to control any potential infestation.
Sweet Viburnum, Viburnum odoratissium, grows quickly in full sun or partial shade in a wide variety of soils. It is moderately drought tolerant but it is a poor choice for salty areas. This plant can reach heights of 18 feet and will spread about the same width. It is generally free of pests and easy to maintain.
Pittosporum, Pittosporum tobira, grows in partial shade to partial sun on a variety of soils. They can reach heights of up to 12 feet with a 12-18 feet spread. Plant should be placed 3-5 feet apart. It is highly drought tolerant so little water is needed after establishment. Consider using all three and staggering them between each other. They all have different colored leaves and the growth habits are complimentary. These are just a few choices but they should be enough to get you started.