I don't know about the thermodynamics, but I'm wonering if something like this would help balance flow:
If you came down on both sides of the "divider" with a ball end mill you would have a bit of slope directing the flow towards outlet, likewise with the bottom opening in the top-plate. Anyway, just a thought, it came to mind while looking at morphling's block too. It just seems to me it would be better having the water directed rather than colliding below the outlet.
I'm not sure how the block will perform but the little I know about milling tells me it will be expensive to make. Also your drawings don't reflect the roundness of the tools on outside corners and such. Probably won't make much difference, but you should take that into account.
peace.
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