I read trought your reply only once, and i understood it completely. It means two things:
-You post in a clear, easy and understandable way and i get it or;
-I've been here for some good time

.
Anyway, i only asked this because i think it 'suks' when i want to cool down my CPU, GPU, chipset, etc etc but cant use a WW or Cascade since they are too restrictive for a system in series, and theres the risc to have much more water passing on the less restrictive 'way' on a parallel system.
Even with the same blocks, because one may havemore tubing, corners and others to turn it more restrictive.
But, in a very restrictive, low flow block, the resistance to water will be ignorable on the tubings, wich could bring some advantages:
-Imagine this teoretic block is 200 restrictive, and on one loop you have 5 restrictive tube and on the water 10.
-Now you have 205 restriction on one loop, and 210 on the other, very litle noticeable diferent flow.
-With such a low flow, 3/8 or even smaller tubing is enouf, because once again it can be ignored;
-Samw with heatercores/radiators, could be chosen a more restrictive/better designed one, since it wont provide any notieable restriction on the sistem;
And the most important, to me:
-You can have the performance of a WW, or close, in 2 CPUs and a GPU, or even more.
The contruction of the block is very complicated, and i dont even know if this measures i indicated are convenient.
Its a teory that i would love to see developed anyway.