GraceSpacing on Staff

[Robert Garrigos]

I have this music to replicate:

I managed to get this:

Still, I need to move the lower grace notes to the left. I can only apply 
GraceSpacing on the whole Score, which doesn’t help. Can I apply it on just one 
Staff?
Also, I need the slur across the Staves but cannot find how to do so.

Thanks.

Robert