Your Right VERY interesting....
I also like the salt.... Very good and DEF the best of the 3.
With the mask.... It looks as if you actually used a bit much compared to what I do. I usually take it and Blot it on a bit of tissue/paper towel and then blot it on the model. This gives it a more random effect. Here is a couple of pictures to help show what I mean.
With too much you tend to get the plate on the lower left. thick spots and not a mottled effect
Here is a side by side using the same sponges just less and more paint. You want the left VS the right.
As for removal... I use a Very pricey piece of technical equipment that you may not be able to get in the outback....
This way works pretty good for me, but it might not for you. I find the hairspray problematic also, and the Salt I have had mixed success. I like the "control chaos" I have with the mask liquid though.
I will also have to do a side by side using these methods, as this has made me more interested in how to achieve different looks and find a way to suit my style!!