Decided to ue the silver base, 4mm spacer middle, and modified the top.
The silver base is currently the same as in the pic. I think I would be sacrificing mechanical strength if I made it much thinner - silver is very soft... Also I think BP thickness depends a huuge amount on the chip and block design, and also I think it would take many trials to get it just right..
I will however cut between the remaining channels as water will not move in them if there is a 4mm gap above them in whihc water can move freely...
The thermal conductivity of silver over copper is not a noticable quantity, I think the bp is about right.
The block will not be restricitive becuase as I said there will be a 4mm middle spacer, which is 40*20 ID.
For the top, I took out the exitisting pipe/barbs as they are a pita the way I originally done them (using copper wire to make the difference between 12mm and 15mm pipe.
I was going to do them the way jaydee116 does his, with end-soldered joints, but as Im uing elbows, I doubted the strength.. also I think he used braize and not soft solder.
So instead, I used a hand drill, and a 16mm FLAT wood bit (
this type - which gave be REALLY sore hands with several blisters..!) to drill two 16mm holes.
Then I braized the elbow in and it never coming out, and its never going to leak.
My flowrate is very high imo (see link above), havent tested this yet but I expect the full system rate to not be much lower than the test with the rads. I mnight replace the rads later on if I think it will improve flowrates.. I wantto put them in parrellel anyway..