I am 225 and my SS is fine for playing.  I agree with the other post that big / technical runs would be a little crazy, but it isn't really meant for those is it?  I don't know how much better the SH would be than your SF on big water.  I don't think it would be much of an advantage.  I think the SS and SF are great boats.  After paddling it I am not sold on the SH.