Tight flat webbing.
Install when soft (like they said), wet helps too, then blow it up tight. Don't wrap D-rings (like I did- DOH). They will bind on the D-ring, and you will blow up the boat and have it waaaay too tight in one section, too loose in another. (Hey, it seemed like a good idea to get it tight at the time). If they just pass through, they will adjust themselves automatically when you blow it up. Some people tie them at the bow, and off at the stern to keep it tighter, but you can go all the way around if you start it off tight enough. Tight is also better for using it to pull yourself back into the raft. I've grabbed a loose one, and pulled it 2ft down into the water, which is worthless. I think if you did just the sides, it would be harder to get in the boat. I like to grab on either side of one of those side D-rings and flounder around like a manatee...
It takes a big man to cry...It takes an even bigger man to laugh at that man.