I made a swiftech style block that's HUGE. The base is 3/8" thick, and 3" long and 2.25" wide. It's got a big ole PVC cap on the top with barbs stick in it. It's all JBWELDed together, and I'm gonna fire it up in a few more days.
(side note on the JBWELD: I COULD NOT BREAK IT. I tried pulling it apart as best I could, and it was solid. I'm sure if I bang it on some concrete, I could eventually break it though )
i would think you'd do much better with a thinner base liss. looks like your w/b can handle some decent flow rates and the water should have no problem carrying the heat away from a thinner plate, just thick enough so that it won't bend would be sufficient imo.
I use a .125"(3.18mm) on my new block opposed to the .1875"(4.76mm) I used on my first. I use a grid pattern on it though so the pins on the top piece match the pins on the bottom so there's no chance of it bending.
that was base to thin.. this is actually waterblock to thin.. lol..
anyhoo.. i got my cu today.. was pretty expensive for just a bit of copper (compared to al)..
and my base is gonna be pretty strudy.. so nm about it being thin..