I use my design wall to spray baste most of my quilts now. It's so much better than crawling around on the floor, running around a huge table, or hand basting on a full out frame. The only ones that I don't do are the ones that I send out for long arm quilting (because they don't need to be basted).
OK, so here's how it's done. Put up your backing and smooth it out on the design wall - wrong side facing you. Pin it at the top and in a few places down the side. Next place your batting on top of the backing and smooth it out. Finally, put up your quilt top and square it up to the backing. Smooth this layer out. Then put in pins at the vertical midpoint, spacing them about 4-5" apart. It's hard to see the pins in this picture - they're half way down from the top.
Place some paper at the bottom of the design wall to catch the over-spray. I use freezer paper and save it for the next time. If you're concerned about getting the spray on your design wall, pin some newspaper around the edges. (I don't do this step anymore, and am careful not to spray too close to the edge).
Keeping the pins at the top in the backing, drop the top half of the quilt and the batting. The pins that you placed at the midpoint will hold these layers suspended. Spray basting spray on the top half of the backing. Carefully smooth back up the batting, starting at the center and working it out towards the edges and corners. Spray the top half of the batting, then carefully smooth up the quilt top. Since the basting spray is temporary - like a sticky note - you can pull up and reposition the batting and/or top to remove all wrinkles.
Next, pull up the quilt top and batting from the lower half and put in a few pins to hold them up. Spray the backing, then smooth down the batting. Spray the backing, then smooth down the quilt top.
Remove all the pins, and take the quilt sandwich off the design wall. Give it a light pressing on both sides. If the quilt is somewhat large, I will either add some safety pins, or I will machine baste the quilt with dissolving thread. Now you're ready to do the quilting!
It's such a fast technique. I hope you give it a try!