It depends.
They open the viewing areas about 8pm but people start waiting in line from about 7pm. The viewing areas are sloped concrete. I prefer being at the waters edge by the railings. Some people like to be further back.
The viewing areas fill up fast, so if your party wants to sit side by side, instead of bunched up, you might want to get there early. People sit in family groups and as the area fills up, the spaces between groups may not be enough room for your group. In theory theres plenty of room, but people spread out. Everyone who has a viewing area ticket will be in the viewing area, but some people may have a smaller space than others. I hope this makes sense.