Background: All my chair covers are black satin. 1/2 of my tables are black satin w/purple runners, the other 1/2 are charcol grey w/purple runners. All the tables have purple napkins.
This is my backdrop:

(pretend the brown is black)
Where I need your help is two parts, we're not having any other white linen at the wedding and we don't know what to do for swagging for the actual table.