1.025-1.026 is what most of us keep our tank at.
Add sand first and then rocks. I don't know how much sand you need. However, for rocks, I usually start off with 1lb per gallon. Some people go with 1.5-2lbs per gallon. IME, 2lbs per gallon is a lot of rocks. Also - remember that later on, you may be adding more rocks when you purchase frags or colonies. The amount of rock you add is purely personal preference.