What's the typical weight for an 11 hr flight with 216 passengers?
With about 65/68 tons of fuel it could be 'round 215/220 tons.
What would the a/c weight be 3 hrs later?
With previous figures 'round 195/200 tons.
At that weight what is your turbulence speed?
It's related to the altitude, regarless of the weight. It's Mach .80
At that weight, at FL 350, what is typical cruise mach?
It's related to the company policy. Usually something between M .81 to M .83