Been lucky enough to sit outside on our last 2 trips to Epcot. I would definitely suggest getting to the podium about 30 minutes early or even changing the ps time to 7:30 instead. 8pm might be a bit late to get an outside table. If memory serves me, there were only about a dozen or so that had a great view from under the awning. I've read that some people will stop by the podium during the day and put in a request, but as far as I know, they still will not guarantee it. During busy times, if you don't take the table that's offered, you will lose your seating altogether.
As for the view, it's almost as though you are sitting on top of the show. Fireworks take off from literally right beneath your feet and you can feel the heat from the globe. Truly amazing.
Good luck