1. The factory jetting is for a sea level application. I think it should be pretty close for you. I don't recall the jet sizes, but a few searches will turn up that info.
3. See pic below. Not the most elegant homemade contraption, but it works.
4. I had mine on and off several times, even re-used the gaskets a few times. Never had any leaks. Just check that the mounting plate is flat and has no casting imperfections.
5. Search for a thread called Weber Set-up and Tune Discussion
6. In the wiring harness.
(Your manual's wiring diagram should show it.)