For the WB design, I'd think about a ridge-less LRR design.
That is basically the waterblock you should above with four outlets.
However, you have a plate which forms a nozzle to accelerate the water and hence get more of it interacting with the base of the block.
I'd go for a slot rather than a hold, and aim to have the slot the width of the block, and then run it at full width initially, and then squeeze it in until the flow dropped off too much, and then bring it back a bit.
__________________
Long Haired Git
"Securing an environment of Windows platforms from abuse - external or internal - is akin to trying to install sprinklers in a fireworks factory where smoking on the job is permitted." (Prof. Gene Spafford)
My Rig, in all its glory, can be seen best here
AMD XP1600 @ 1530 Mhz | Soyo Dragon + | 256 Mb PC2700 DDRAM | 2 x 40 Gb 7200rpm in Raid-0 | Maze 2, eheim 1250, dual heater cores! | Full specifications (PCDB)
|