What direction to point returns

Since your returns are on opposite ends from each other, I would be inclined to point them slightly upwards and in a clockwise (or counterclockwise) direction to help encourage water flow in a circular pattern in hopes of getting surface debris to the skimmer. The wind will play a major role in how well that works, but that would be my preference.

Well, we as pool owners have to be realistic. Depending on your return jet water pressure, pointing jets down may or may not help at all. I have 6 return jets and if I point them down they won't do much. After 2-3 feet you don't feel much of anything. With only 2 jets, you don't have many options. Circulation is important, but you have to decide what's best for your pool. There is no one solution for all. Pool shape, depth, equipment, etc all play a factor. Experiment. Toss a couple ping pong balls on the water's surface and see how well water moves to the skimmer. If your water is balanced properly, algae shouldn't be an issue, but if you feel that pointing a return downwards is more beneficial, you certainly can do that.