Good job making that tutorial.
Just a note, it is not necessary to continually change the quick mask mode from 50% to 100% and back to 50% and so on...50% is fine for most situations.
I actually make my selection with the magnetic lasso usually, and then fine-tune it in qm mode.
Since my job is doing photos for the local newspaper (amongst other things) I have my qm mode changed to "masked areas" and the color "white" instead of red, and the opacity at 80%. In this way, I "draw off" the portions of the image I don't want to see whenever I'm doing a cutout. It is very useful for cutouts, because the white acts like the background color, but since it's only at 80% transparency I can see through it just enough. Hope that makes sense.