Anyone know how well the stem length matches posted dimensions? The technical drawing is a bit too grainy to see what's really going on and the head angle is missing. If I really squint it appears like the the nominal stem length is actually measured perpendicular to the steering axis to the center of the bars, including the 8mm rise? That way the corresponding traditional stem would be a few mms shorter, no?

Or in other words, I currently ride a -7° 100mm stem and it's a touch too long if I'm doing Z2 and the spacer stack is kinda ugly, so I would maybe want the 100mm HBR17, get two or three mms shorter reach in the X axis and remove spacers by however much the 8mm rise amounts to in the steering axis?