I took a digital humidity gauge on a flt to YYZ last week. In the climb it rapidly dropped, and settled down in the cruise at 7% relative humidity. We had close to 200 pax both ways and 2 different 777's.
I found this to be much lower than I would have guessed at. At home it reads about 55-75% depending upon how damp the weather is. A Canadian government health site recommends a humidifier in the home if it drops below 30% as this is the level below which health starts to suffer.
As an aside with a cabin alt of 8000' blood oxygen saturation will be 92% at best as apposed to 98-99 at sea level.
The 777 autopilot can be eager to wind on bank (roll) if we get a direct routing requiring a change of heading with the next waypoint close by, as it draws the new course on the map then cranks on the bank to achieve it. Switching from lateral nav to heading prevents this but you then have to switch back to lnav once on course.