We were there last January, starting on the 10th......and we never had a problem finding a seat....showed up maybe 30-45 minutes so we could sit and eat hot dogs and popcorn while we waited for the show.
I'm sure cutting back to 2 nights will certainly up the crowds at each performance, but really, when we were there we always sat in the section directly in front of the food stand.....and there were always plenty plenty plenty of seats in our section....sometimes entire rows that were empty, except for the feet of the people in the row above.
Will you be there long enough to be able to try it both nights its offered? If so, what I would do frankly is make an ADR at Sci-Fi for the first night....then head over there maybe an 30-45 minutes before the show (or however long you're willing to wait....sit and people watch, or maybe ask Sci Fi to package your dessert to go and eat it while you wait). If the crowds are bad and you can't get a seat, then go do something else.....because my second recommendation is that you make an ADR for the second night with the package. If you get to see it the first night, call the next morning and cancel your package ADR. Someone wanting to go last minute will send up a silent prayer for their luck.....and you'll have gotten the meal you wanted and the show you wanted.
Unfortunately you're going about the first week that the change is in effect so you won't have the benefit of others' experience that I'm sure will be reported here as soon as they get home!
