I currently run the HBR17 on my LCG071 as a Gravel setup, works perfectly fine for me, also on gravel.
I ordered a 100x380. They measure exactly 380(c-c). Also they measure 100 in length. Measurement on the bolt looks off in the picture, but is perfectly centered.
Reach of 75 and angle of -7 also looks to be correct.
I tried to capture the rise, also 8mm rise looks fine for me.
Stiffness and ergonomics is fine.
Also if you are wondering: to get it painted is only 20$ extra

If you anything else, just let me know.
What I don‘t like: Top cap could be more precise (maybe because it is painted). Computer mount faces straight forward, a little tilt towards me would be better. Maybe I need to try the titanium mount.
For comparison: I also have a Vision Metron 5D evo on my roadbike.