appreciate this is an old thread, but im looking into this as well now. The way you'd assemble them would be identical to the IFX dowels - align the concentricity and the top face (very likely with an offset from the top face).
Would B&W be interested in defining these screws? If not I may be building them fully custom, but if you'd build a starting point that would be great, I think many users would find it helpful.
I am most likely be looking into DIN 913, DIN 914, DIN 915 and DIN 916
Please let me know if I can provide more information about this inquiry