The most impotant thing is that the siding is clean. Use a power washer if available. Otherwise TSP and a scrub brush. Any premium brand exterior paint will do. Try Benjamin Moore's Moorgard Low Lustre. But, to the paint add a product called E-B Emulsi Bond by the Flood Company. It will help the paint adhere to the siding, especially if it is chalky. Spraying is fine. If you have a calm day and your neighbors aren't too close.