Here were my observations from the timing chart.
1. I always divided the OT movies in two parts.
a. Tatooine and Death Star
b. Hoth and Cloud City
c. Tatooine and Endor
And it's not quite that simple. At the very least ESB is more in thirds than halves. Still, each movie has about 5-7 set pieces or environs. It's more than I would have thought, but still relatively simple.
2. How similar ANH and RotJ are in reverse. ANH starts with three different perspectives (Luke, Leia and Vader) and ends with a single unified narrative. RotJ starts with a single unified narrative and then splits into a three way split at the end.
3. Luke and Han are introduced relatively late in ANH. They're reintroduced immediately in ESB and have late intros again in RotJ. But it is ESB what keeps introducing new characters throughout almost the entire runtime. ANH and RotJ mostly lay their cards on the table in the first act and let them play out through the second and third.
4. The movies are almost all the same length, though they did get longer by a minute or two each time.
Speaking of acts: Looking at this (or not) can you call the act breaks in the films?