Great guide and very easy to accomplish.
But even simpler is it imho when you put the Macbook opened but keyboard down on the edge of your desk (put mousepad / sleeve underneath)
Use your lap or womb (whatever is closer ;—-) to stabilize the screen while dissasambling - sounds more complicated that it actually is.
I find it much more convenient than having the macbook turned 90° and standing on its side. But everybody should do as he/she likes.