It kind of depends what you are planning to do after the parade. More than half of the guests leave after the parade - if you;re one of them, then chose a spot that's closer to the exit so you're not behind everyone else.
If you're going to stay (and I love the way the park empties out after the parade), then you want to be in the back. I had a spot just where the parade turns off the bridge and heads toward africa that was good.
I will warn you that sitting and waiting for a parade for any length of time in July will be brutally hot. I avoid parades in the summer. But it is my favorite parade, so if it's your only chance, get yourself some sort of frozen concoction and settle in!