Just look at old videos going back to the 50s and 60s and you can see that.
USC as you state has always liked the north sideline.
You want to talk about hot? Try sitting in SunDevil Stadium in Tempe AZ on a sunny September Sunday afternoon. I was nothing but one big salt cake by the end of that day and could barely walk. The Coliseum is not a comfortable stadium. You have no cover from rain or shine. You either get the full brunt of the heat or the cold or the wet but there is no place to hide. And if your fat or over 6'3" in height its not a comfortable stadium either.
For fat tall people the most comfortable seats are the bench seats by the Peristyle end. Up high they are not bad seats you can see the whole game and your knees are not compressed and your fat butt is not squeezed into a seat made for a jockey.
Grits