What components will they be cooling?
If you dont mind some constuctive critasism, i can think of several improvements for them that may even be easyer to make.
Instead of a Z shapped large channel, make several small channels so that you get a lot more surface area and more effective cooling. It would make it more restrictive but not by that much, as you could have them quite wide so it would be almost the same.
Also I would think this way would be easyer to make and possibly waste less material, Ive done similar with my gpu block, and I used a dremmel to cut the channels. what tools do you have to make yours? a drill press or mill would be the only easy way to make those big channels quickly. Or you could do something like a #Rotor by dirlling very close together holes, so that the area left creates pins for hte water to flow over.
Also from the colour in the renders would that be alu your intending to use or copper? If you can get copper I recommend it, as alu will give corrosion problems, worse performance and although its cheaper, I think copper is worth the extra for that.
What program did you use to do the renders btw? they look good
