EVGA Backplate is NOT compatible with the EK Waterblock! The EVGA Backplate uses both screws and holes of size 2.5 while the EK Waterblock uses screws and holes of size 3.
The size 3 screws from the WB do not fit through the holes and fittings of the BP and vice versa the size 2.5 screws don't fit into the WB.
While trying to assemble the WB I actually considered the solution of expanding the BPs holes to make the size 3 screws fit but even the screws heads wont fit into the fitting when expanding the hole itself... I actually gave up and will now send the BP back to EVGA...