Rosberg is the only one we can compare against which puts Hamilton around the level of Webber. Until he races against someone else I'll be keeping Lewis down at rank 5 for fastest driver on the grid.Lets say that Lewis is the best driver on the grid, and Stroll is the worst (could argue others, but Stroll sucks).
Both of those drivers in a Mercedes and I reckon Stroll would be at least 1 second off on flying lap pace.
Even at 6-8 tenths that's the difference between being on pole and being 3rd-4th in their dominant years, likely 5th-6th this year.
The only drivers I could see replicating what Hamilton has done at Mercedes (and even then they wouldn't necessarily be odds on) in the same circumstances (vs Rosberg then vs Bottas) would be Vettel or Alonso.
Max and Daniel would have probably won a title or two in the car, but not 5/6.
Also I wouldn't have the gap near a second between Lewis and stroll, half of that tops. Unless someone botches a lap there is generally only a tenth between teammates across the board.