45 minutes - 2 hours
The rear camera in my iPhone 5 developed spots and a very visible dust speck a couple of weeks ago. I figured it was just dust between the camera module and the sapphire lens. I did the take the phone apart and flip the camera out if the way and blow the dust out trick to no avail. It was a contaminated camera module.
The repair went very easy following your guide. Only problem I had was I lost one of the shield screws for about thirty minutes. Some how it managed to find its way under the container that I put my screws in.
The only advice I have is that the screen can come out very quickly when using the suction cup, mine let go so quick I thought I damaged the ribbon cables. See my photo of the before and after results. The pictures are out of focus on purpose because the defects show up better