Tyrannosaurus rex vs Tyrannotitan chubutensis

You can't scale those two isometrically totally properly, they have a difference in robustness so scaling won't work properly. Still, it is more proper to scale Tyrannotitan chubutensis from Giganotosaurus carolinii rather than others such as Carcharodontosaurus saharicus, since Tyrannotitan and Giganotosaurus are more closely related.

1. Look for dates. Many of those sources base on the same estimate.
2. This size advantage you are suggesting doesn't make it a full mismatch or anything one-sided.

Maybe bigger 

Sue could have been about a ton lighter, the density used by Hartman is a bit too high, if we scale Tyrannotitan from related species we also get something more or less the size of Sue, I don't think the size difference here is even worth mentioning. And about Tyrannosaurus's gape, the craniomandibular angle wasn't very wide, though it is wide enough here. We could try using trigonometry.

Gape = jaw length/sin((180-gapeangle)/2)×sin(gapeangle)

An angle of 60° and a jaw lenght of 1.4m, you get 140cm, though it's worth noting that it probably didn't open its mouth that wide, crocodiles for example do not usually go beyond 40°, so that gives 96cm, which is actually enough to bite an entire torso.

I say T-rex wins.