I have a NRS Otter 120 SB, and I put a third thwart in it. I'm on the water twice a week with 4-5 people, the boat R2's like a dream. With 6 people you are sitting low. I typically run the New, Nolichucky, Ocoee, French Broad, Dirty Bird, and just got back from Gauley. No problems with stability, except large curl waves. By large I mean 6-10ft (east coast stds). They seem to be the direct result of my flips, but hell I've seen 15ft rafts flip on those large curlers. In hindsight I could have gotten away with a 13ft, but It wouldn't have the same fun factor or R2 as easily. Good luck!!!!