Best way to approch this - need some sort flow along surface command

So I need to get the polysurface on left to match on right model on the top so the 2 yellow lines all match up.

best command?

Thank you

end result would look like this but much neater and a closed polysurface

Looks like Scale1d would do it.
But the corners won’t fit, seems like a different radius value.
You would have to extract all the sides of your cover, extend the sides of the box, trim and join…

Thanks - in the end I created a base surface and a target surface and just used the flow along surface command

I think the Orient and Orient 3 pt commands would work nice. There is also a scale option in the command.