the only thing that i am dubious about this design are the holes. imo those holes could make the water get stagnant.
if i were you, i would make only holes above the cpu die and not that deep.
if you want to catch some idea, the dimplets i and hara designed for our water block with you can see in the avatar are 0.7mm diameter and 0.3mm deep. we were planning to make them even smaller
about 0.4mm each in diameter, but our machinist did not have that type of mills.