Small World has more viewing areas than Main Street. On Main Street, the front row sits on the curb and there is room for 2-3 people behind them.
In the map below the purple line is the 8:45 pm parade route (10:50 goes in the opposite direction). The teal stripe is similar to Main Street in that the front row sits on the ground and there are 3-4 rows behind them. There are areas where the teal is a little thicker. That is a roped off region that can accommodate maybe 10 rows of viewers. I wouldn't want to be 10 rows back as the view isn't very good. The red area is a raised terrace. There is quite a bit of viewing from up there. The yellow area is generally reserved for VIPs.
View attachment 973239
After PTN, many people leave. There is plenty of time for the remaining guests to move closer to Small World to watch the fireworks. After fireworks many more leave so that a much smaller group remains for Tapestry of Happiness.
Below is a picture of the terraced area that I colored in red. The brick area on the street is where the first row has to sit and the people behind them stand. Most stand on the upper level. Some sit on the benches or steps (although the steps aren't the best view).
View attachment 973241
The terraced section on the right in this photo is used for VIPs. There is seating along the white fence on the opposite side of the street. They don't open that area for seating until approximately 1 hr before the parade.
View attachment 973244
In the picture below, the yellow indicates the edges of the viewing areas. People can sit/stand on the brick in the foreground before the yellow line. They can stand on the other side of the street (where the people are walking). That's the area that can hold quite a few people. However, it is flat so if you have a tall person in front of you (or a child on shoulders), it might be obstruct your view. Front row for that area lines up pretty early.
View attachment 973243