the mask you make in step 8 can also be made with the clipboard.
select the layer you want to use, press Ctrl a- Ctrl c and than Alt click on the mask you want to edit and press Ctrl v.
There is one complication that occurs when the source layer is smaller than the canvas. The placing in the mask center, but is easy to fix, by creating a selection of the layer you want to use in the mask (shift click on layer thumbnail) and then place the clipboard data in the mask (Alt click + Ctrl v).
this technique is maybe not so fast but its more low-tech and can be used in older version of photoshop