Yep, basic plan is to have about 11 stages for characters.
10 where they can actually move and anything above that where they cant but can use a massive attack to reduce their size.
As for the story events, we do hit some very large sizes on Rim already but you know we can always go bigger :D
Ah and also i do plan other forms of size in the future, for example a character that becomes gigantic not just by fat but actually like building sized.