Hi
Rotor 
(Rotor is my "Yoda" btw)
To address some of the points made here.
The block channelling is not the prettiest I agree but for the items being cooled it is more than adequate. This is mainly why I didn't attempt making a CPU block but bought a better wide channeled milled one, (and modified it a bit)
The way I have my flow ensures there is no overall flow restriction as it enters the most important thing to cool best first, the CPU block. It's then split by low restriction manifolds to all the other lower heat producing items. A smooth channelled design in all these other blocks may increase overall flow a small amount but the rough surface of my channels will certainly help surface area and turbulence, (if it really makes any detectable difference). one other thing more important than that IMO is the way I cool my coolant, all blocks receive lower than ambient temp liquid anyway.
JimS
Soldering two pieces of copper together is a very strong method and they wont pull apart as long as the solder joint is created correctly. if you get a dry joint or the copper is not cleaned well as you go just prior to tinning, it will be weak. It's a good point you make however, but if the pre-tinning method explained in my build is followed, the joint will be almost as strong as the copper it's self and leak proof.