Few days ago I was looking for new info about Joseph Pierce Farrell's techniques (Manifesting Michelangelo) and I saw new videos on his website. The cases on the videos took from 45 minutes to 3 days (probably for few hours a day for 3 days). Most of the results are really visible, not just some blurish before/after photos. Some of the claims are even that you can see the changes in real time.
This is the 45 minute change video:
This is the 3 days change video:
Maybe it doesn't give the best clarity but at least we have an idea how fast a visible change can be done.