[Puzzdre]

Considering the accuracy of the drill press, the base thickness is, as g.l.amour said, 5 mm (probably more like 6 mm).
Dunno if it's gonna change something, tomorrow I'll replace inlet 12 mm ID barb with 10 mm ID.
Yeah, I figured out that maybe a little thinner base would be better. I'm not dissatisfied with this block, just wanted it to perform better in a given setup than my old block, which looks like this: 6 mm ID drilled in s or z...