We went the weekend of Nov 17th last year and there were different procedures each night as they seemed to be trying to figure out how to deal with the crowds. They did run it before it was fully dark and you could still see it very well but the colors don't pop like they do when it's fully dark. They ran it back to back a few times, separated by about 10 mins sometimes, and ran at the scheduled every 20 mins sometimes over the 4 park days we were there. They did also run it after park close at least two nights.
It's better to go to a later showing. The early ones were jam packed mob scenes but the later shows were both darker and had less people. Last I looked at times for that weekend (we'll be there too) I thought the park was open until 8. If not, I would expect they would extend it.
Edited to add, IOA is scheduled to be open until 8 the weekend of the 17th and if it's really crowded for the show, I'm guessing they will run it after closing again for opening weekend like they did last year. TP will catch up eventually. They seem to be more timely with Disney updates than Uni ones.