According to the post itself, 3 of those 4 hours were spent removing the glass and then replacing it after realising it never needed to be removed in the first place. If you skip that step it's probably a lot faster.

> It took me a little over four hours to do this, but nearly three of those were spent trying to replace the glass display that I shouldn’t have removed in the first place. There were also some other distractions along the way.