I bought all the sets a year or two ago. I too did the spoon test. Unfortunately, my skills with an airbrush weren't too great at the time, with acrylics, doubly so. I did not get near the results Paul has shown. My brush painting of these was quite hideous to boot.
My goal was to put the colors from the Datafiles on a few models and see what the authors saw. When I put the AK spoon tests up against the Methuen Handbook, none of the AK colors matched the Datafile colors. In fact, I don't remember any of them being close. But, as you can see from Paul's picture, they are lovely colors that go well together. If I wasn't obsessed with the silly notion of reproducing the datafile colors in the flesh, I would consider using them.
Stuart