How should I connect two beams to a post at a corner?
Beams typically rest on their posts or trimmer studs. This case is no different, really, and there's no rule that says you have to have a chunk of post running up the height of the beams. I'd miter the beams at a 45 degree angle so that each rests on half the post. Screw them together well and toenail them into the post. It'll look something like this:



8 feet is a typical room height (92-5/8" precut studs with 3 two-by plates), and that's what's normally used for porches as well. Your situation may call for something else, though. It depends on may things.