I am making a king size bed topper for friends. and the bed size mattress is 78length x 76 width . I do not have a bed to lay it on here ;(:(>> so going blind.. I imagine it to go down a couple of inches over the edge of the bed.. and account for machine quilting as well. The drop of the bed is 14 inches.. which may or may not even matter.. How big would you go? I almost want to go to a bed store and lay this on top lOL>