I had a prolite and racers choice single ring pistons sitting on my desk so I decided to take some rough measurements. Here's what I noticed. Pertaining to the single ring piston: Its longer when measuring from bottom of the skirt to the dome. Ring groove is slightly closer to piston crown and the ring is a little bit thinner (less drag). Piston has a larger diameter (tighter clearance). While the length from wristpin to dome is higher, wristpin to skirt distance is shorter. Wouldn't this suggest that the piston is allowed to travel further therefore reducing the squishband? Or at the least, bump up the compression a bit? Currently on my phone, will post numbers and pictures when I get to a computer tonight.