I have used safety pins all around the perimeter of a baby quilt sandwich and put it on my Q snap frame for quilting. I didn't bast at all but starting in the middle and worked out from the midde section with all the layers taut. This way I knew there were no winkles and I pressed down gently on the area I was working on to give it a little slack. I think you could needle and thread bast your king size quilt on your Q snap frame if you did it in consecutive taut sections.