I've made a waterblock that is the same as this design. Instead of using the screw brass fitting, I use copper pipes and silver solder the whole unit together.
I would not recommend the use of screw fittings for the inlet and outlet. The 3 mm thickness cover plate for holding the fitting is inadequate. It may not hold for too long before it starts to leak, as there are only 2 to 3 threads that are holding the fitting to the block which is not recommanded as the standard fittings are constructed with taper treads.