I highly recommend Optics Trade EU, top-notch service, lightning fast delivery via “Express Mail Service-mounts”. Will buy again.
The product: Typical Recknagel, perfect fit and function, no complaints, very good value for the price.
Regarding CZ clamp-on mounting rails, I think the Recknagel version having the positioning/locking lug incorporated into the loose clamp would allow for some possible tolerance compensation if needed, resulting in basically stress-free mounting of the rail when the bolts are torqued.
Bolts are M4 10.9 (Recknagel Information), could be torqued up to 4 Nm. I use 3 Nm, lightly oiled, works.
(Posted on 21/11/2016)