You and I have already debated this, and I will say again what I said then. I have no ownership share of any Rams player, and I am only presenting what I see as an observer. Even if we set the bar at 250 touches, there were only 9 RB to his that number last year. Even with another game this year, I don't necessarily think all RB will see a 6% boost in their numbers. Injuries are still injuries, and workload management is still a thing. Teams need to keep their guys fresh and available throughout the season. For a team like the Rams, I especially think that will be the case because they will want guys healthy for the post season.
IMO, Henderson is best suited as a role player / part time back. I could care less what a coach says. If he claimed Henderson was the second coming of Walter Payton, should we believe him and does that make it so? McVay is saying the only thing he can say. He has to keep Henderson's confidence up. Maybe he will see a few extra touches until Michel gets up to speed, but I don't see Henderson getting the workload you are suggesting.
Henderson is probably best suited as a 10-12 touch per game back. Michel has averaged 15.5 touches a game over his career. Last year, the three headed hydra at RB in LAR averaged 27 touches a game. Maybe I am crazy, but I see Henderson still getting 10-12 touches a game and Michel could get 15-16 touches after the first month of the season. If you want to give Henderson more receptions than Michel, feel free.
That might be a little high, as I do think the Rams will probably pass a little more this year having less depth at RB. So maybe Henderson gets 10-12 touches and Michel gets 13-15 touches. But I don't see Henderson getting 250 touches and Michel getting "backup" work and 75-100 touches on the season. Like any other team, should one of those two get hurt, the other guy will see a big jump in touches and fantasy numbers.