One thing I noticed that is pretty consistent in the inflation genre is that the inflation is relatively rapid. Occurring over seconds, minutes, occasionally hours. But you never see any stories involving inflation that takes over days, weeks, or months.
For some reason, I like the idea of a person expanding at like 1/4" per day. I think it's partly because part of the enjoyment for me is trying to do everyday things while expanded. The rapid expansion never seems to get into that.
That's a great concept! I also like the challenge of trying to move and act while inflated; it's the central theme of one of my stories.
There's a lot of story potential in a case of gradual but inexorable inflation. Maybe a woman has an incurable medical condition that will cause her to inflate into an immobile sphere, and she has to enjoy her mobility while she has it while coming to terms with what's happening to her.