I prefer doing the machine quilting to piecing, so sandwiching is actually part of the fun for me since it means I'm that much closer to being able to start the quilting.
I use a method similar to Kitsie. I butt a couple of tables up to my large cutting table so that I can support as much of the backing and batting as possible without having to get on my hands and knees. I don't clamp or tape the batting to the table, but I do align the batting with the corner and two perpendicular edges of the table (for large quilts the batting hangs off the other two edges). Then I lay the backing over also aligning that with the table edges. Peel the backing back as far as possible without it falling off the table, spray a strip, lay it down and smooth, then spray a little more, lay it down and smooth until done. Slide whole thing over so parts that were dangling off table are now on table and repeat procedure until whole backing is basted to batting.
Flip over so batting is now face up. lay top over and do same procedure.
Goes pretty fast once I've got everything lined up. For big quilts that are going to get a lot of handling as they're quilted I also add some pins here and there just to make sure nothing shifts while quilting.
If I'm doing a quilt with complex quilting and a double layer of batting I usually then machine baste it with a grid that's about 5 inches apart so I can remove any pins I added before actually starting the quilting.
Rob