How does one know at what tilt to mount the Luxos U.
Why is there not a line on the body that is to be horizontal at the correct tilt.
Do I just go out one night and fiddle with tilt until "that looks pretty good"?
Please help, it is not an inexpensive tool.

Find a flat, level area with a nice, level wall about 7-10 meters away and aim the beam cutoff at about the same height as the lamp itself so the top of the beam is more-or-less parallel to the ground. This will get you in the ballpark and you can adjust up or down a little bit to suit. I have the B&M IQ Cyo Premium and like the cutoff a little bit above this, not so much it irritates oncoming people on a narrow MUP (I've personally asked people if my light was bothering them, which it thankfully wasn't) but enough to throw the light a little further.

Is the 'beam cutoff' readily apparent? Is it distinct?
So far, on the open roads, I haven't really noticed a 'beam cuttoff'. Maybe this is because I haven't been looking, or the lamp is tilted the wrong way. I am guessing the lamp is tilted too far down, because there is much light down in front of me and not much out beyond.

If the light is aimed too low, the beam cutoff is visible as a fairly sharp line (often 5-10 yards in front of you) on a level road. The easy way to aim the light is to leave it just tight enough that you can move it, then adjust it so that line just disappears. At that point, the cutoff is illuminating the "horizon," and the wash will adequately light up most road signs and show oncoming traffic where you are. Once you've found the sweet spot, simply tighten the mount.

Here's a pic from the similar cyo -


The cutoff should be apparent if there's something tall and straight that it's pointing at - a wall, or pedestrians. I try to aim mine so the main part of the light doesn't light up their face or chest (to keep the light out of their eyes) but lights up their legs. As high as it can go without getting close to getting into the face of pedestrians or bikers.

Wow - mine must be really low.
I can't wait to get it out some night and adjust it properly.

I can't find a dark enough place to do this in the city!

I use speed limit signs to level mine. You should be able to see the light on a speed limit sign about 200 feet away, but not closer. It's a judgement call