I've broken in two [mostly] new Zs at this point. I basically just used my ~25 mile commute.
Focused on varying engine load and RPM, tried to stay under 6k where traffic speeds permitted (under 4k is a joke and will get you killed). Always let the engines fully warm up. One or two hard pulls through all the gears per trip, engine braking often for deceleration. Keep any runs above 8k brief. Dino oil changes at 200 and 600 miles, semi-synth at 1000. Good to go.
Rode it like I was going to ride it normally, just with a little extra mechanical sympathy, NO cruising.
Biggest change between break-in and normal use is that I'll ride WOT on 55mph roads for an hour without worry.
It also seems worth mentioning that my 2017 lived its first 15 miles as a pit bike, being wheelied by various racers and toting around family members two-up, but never with a cold engine. It got new oil before I took delivery at 18 mi and has been a peach so far. I think it rides better than the brand new 2018 frankly, but maybe I'm just biased because the '17 is mine.
Dropped a gear... . . . . . . . . . . ...still here