According to here: https://www.billboard.com/articles/news/5862286/dream-theater-planting-seeds-for-album-no-13
Illumination Theory is the closer, although it's not a direct quote.
I initially had a strong feeling they were going to play Octavarium. (Please ) Although if IT is the closer, then maybe not, I don't see Octavarium as the kind of song that would be put in the middle somewhere.
Octavarium to end Set 1, Illumination Theory to end Set 2. Problem solved.
That's an abusive amount of music for the guys to handle in one tour.
I mean, they COULD play two 18+ minute epics in one show, but history shows us that they typically do NOT do that. Sure there are longer encores they've played in the past in addition to playing the latest album epic - On the tours supporting
Systematic Chaos, they closed their sets with "In The Presence Of Enemies", then played "Schmedley Wilcox", a 21 minute encore medley. And these were for shows that were only 2 hours long, and not "Evening With" shows (which have been 3+ hours long).
So, while not entirely IMPOSSIBLE, it's less likely since they rarely play two long epics in a single night.
HOWEVER, if they encore with their latest epic, as they did with "In The Name Of God" on the tour for
Train Of Thought, they could do the same this time around and close their 2nd set (or their 1st set) with an epic. Honestly though, it would ONLY be either "Octavarium" or "A Change Of Seasons", IF they do do that.
However, considering the amount of material they've yet to play with their latest line-up and the appeal to play more of their back-catalog with this line-up, I doubt they'd take up 20+ minutes to play a SECOND epic when that time could be devoted to 2 or 3 other songs they've yet to play together on stage. Personally, I'd rather see 2 or 3 other songs played than either of those epics.
Now, if they did a shorter epic like "In The Name Of God", "The Ministry Of Lost Souls", or any of the longer tracks from ADTOE, then they'd still have plenty of time left in the set for more songs. Who knows...guess we'll see in a week or so!
-Marc.