I know this very well.
Your point was that you wanted to render at 480 x 9600. That is not possible with the top camera unless your top view can be set to that size (you'd need to have a pretty big screen for that).
Furthermore, like I said, with the top cam you cannot render final quality render images, all you can do is render previews.

When you do a normal render, you're always rendering the main camera view, that's why you always get a perspective render, like you said.

If this isn't clear yet, I strongly suggest that you read the manual, section about cameras. I don't know how to explain this any better.