Would'nt it of been easier to use holes rather than tubes?. bit like a showerhead?...
Can't wait to see results. How about a mini heatspreader plate(ultra thin between ridges, 0.5mm with 1.5mm+ high ridges) to go on the core?, with ridges or pins to spread the area?. I don't know how you'd fix it though. AS3 mixed with AS epoxy?.
Or individual Cu pins stuck with epoxy?, area & turbulance?...
I like the idea of direct die cause you're hitting the core sides with H20 as well as the top
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Could you lay 'strips' of Cu across the core to increase surface area?, that way you would'nt need a 'plate' with a minimum thickness base...
PS. would the outlet be better recessed?, for flow patern?. rather than protruding into the 'chamber'...