Where to begin, if the water splits two way and the combine cross section is the same as one big chanell, the velocity would pretty much stay the same (it all about area) , and at the same time my lenght of the chanell are that way a lot shorter.
Next thing you saw correctly ,I do have a nozzle inlet on pleksy block and if the narrow part is only very short it doesn't restrict flow too much and at the same time it speed up the flow impacting in to the center of the block.
Here are pics. of my finished block.
I must say that this is only a prototype, and I will change few thing when going cnc way. So all clever suggestions are welcome.