Re: Is it best to use hotplate or a hot air gun to heat up an iPad before removing the screen?
You can use a hot air gun, the shop I work in uses them but we are also very careful with them. You can melt internal parts easily by using too much heat but you can also damage tablets with a hot plate if you don't know what your doing as well.
The link to that tutorial is also pretty accurate but a few things that I would change is the tools and process of where to start. I use a palette knife to get under the screen and start prying and when the larger sections are coming up in one piece I use the plastic black spudger tool to gently pry the glass while heating it. I start at the top on the left side and ove toward the right side then down the right side and end up near the ribbon cable.
This way I have pried most of the screen up before getting near the wifi cable and can get a peek whether the wifi is stuck to the screen or to the frame. You also can heat the left edge and open the tablet screen from the tablet like a book and not worry about wreaking the cable if your going to be using the same screen again.
It mainly comes down to personal preference but the main thing is if your going to be doing this as a job you get a good workflow that works for you and stick with it. ver time you will adjust how you tackle the job to make it easier on yourself.