It almost goes without saying that they are going to have to cut a very substantial chunk of the play out. So currently Part 1 is 2 hours 40 minutes and Part 2 is 2 hours 35 minutes, take away two 20 minute intervals that is around 4 hours and 35 minutes stage time. I would say the most stage time they can do in a single version is 3 hours at absolute maximum so I estimate they will lose over a third of the show easily. I guess they will make sure they include all of the “big effects” scenes as a starter.