This poll revolves around the rate of speed / elapsed amount of time within the context of the story that a transformation takes to complete itself be it Amazonian, Giantess or Mega in scale size.  The choices in formula range from the fast pace of a classic She-Hulk metamorphosis up to those ultra slow ones that take the better part of a story to fully illustrate its impact on the growing subject as well as the people and environment around them.  

I like punctuated episodes of growth.  So gradual in the sense that she doesn't instantaneously become an amazon, but punctuated in that there are multiple episodes of rapid growth.

I would say that it depends on the story, if a She-Hulk type, then make it quick.  It certainly wouldn't pay to have to say to the bad guy, "Give me a few hours bud then we'll really rumble."  If on the other hand it is a permanent change story line, then make it take days to complete the change.