I would be in favor or of basting in a grid pattern , - maybe using herringbone type of stitching
since I tend to go for overkill, I would make the grid about three inches apart.
Also start in the center and work towards the edges.
i had a lot of overhang- quilt bigger than table- and I weighted the sides of the backing with long rulers to help minimize wrinkling of the backing.
I made a " casing for the rulers ( yardsticks, four foot rule, curtainv rodd) by folding the edges of the. A king over the yardsticks and pinning the fabric to itself.