Med>Large>Huge from all levels of AA
5 increases from the total levels of Titanic.
So at max off those I'd be Colossal+3
And well, depends.
The AA version of swallow whole, an enemy 1 or more sizes smaller than myself. While the Titanic Creature's Swallow Whole is 2 or more sizes smaller than myself.
So uh, Colossal+1 or +2
....I'm hungry, gonna go find a village or two to snack on.
Really the choice of which to use is annoying. The AA can hold more, but the Titanic is better in every other way. More damage per turn and MUCH harder to escape.