well i spray baste my quilts on a folding table using a six foot long by 1/2 by five inch board. it's a flat baseboard actually. I fold one long side onto the board and fold and fold and fold until i can't reach more across the table. then spray baste the batting and unfold the quilt/board once and pat down, then unfold and on and on. then move to the other side and do same. then move quilts to get the ends and fold it up the same and finish.
I haven't done a king size this way yet though but it's work on smaller sizes very well.