First on the 'walimex Softbox walimex VC & K & DS Series ": This has the side three patch per rivet" cube "made of plastic, for screwing into the Compact Flash Holder. However, are still below this cube each about 1 mm high pieces of plastic with a second rivet, probably to the cube to save them from a rotation about the first rivet. However, precisely this additional, 1mm high plastic pieces obstruct the easy screwing in the supplied Compact Flash Holder enormous. Rather, I succeeded in doing so only with much force, and only after repeated insertion and removal notches came into existence in the additional plastic pieces, so that the attachment to the compact flash-holder can be done with a little less force. (The small locking screw on the outside of the compact flash-holder by the way only intended to prevent accidental unscrewing of the adapter.)
Now to the already mentioned "walimex Flash Device Bracket for Light Modifiers", which should be referred to rather as "system flash-holder" or "Aufsteckblitz Holder" probably. Although he has an integrated screen Eiger - but by the whole construction is one of the adjusting rods in the way (with which you can adjust the holder to the height of Aufsteckblitzes) as soon as the softbox to more than 10-30 degrees (depending on Flash size) down will tend.
After I was able to work around this problem by installing an intermediate piece, quasi renewing my Aufsteckblitzes, I discovered next that softbox flash holder and together reach a weight that is almost too much for the screen Eiger. Only when I firmly turn the retaining screw with extreme force, the softbox tilts by gravity is not all the way down to (there is no gradual engagement here, as in many other screen ball-).
The basic idea is so good, overall, this solution does not appear but really thought through.