BB2K > Yep, that's Debugger on Cooling-Masters too, he used chemical etching (home-made), a very fast method to cut copper plates at any forms, you assemble the plates to make channels and you get your WB (like Atotech at horizontal or 1A-Cooling at vertical).
XyBeRWaReZ > Such WB have low to moderate pressure drop, the thinner channels you make, the more channels in parallel you get, the less pressure drop at final until a certain channel width which is optimal, and if you go below this width, pressure drop will increase again (near 0.1mm, calculations could be done). My 0.3mm channels WB is less restrictive than my 0.5mm for a same total width for example. It's a good design to cool TEC if you want, but you aren't forced to make small channel, 0.5-1mm width is enough (depends of your milling capabilities and final costs
) . in terms of perf, you can make pins, it's a bit better in general because of boundary layer disturbance (I made some too).