Help with ski upgrade

Hi everyone, I have been a pretty good skier since I was about 15 years old (so about 15 years now) and in the last 2 years have got into short line skiing. I ski on a 5 year old O'brien Allegiance and like it but am looking to upgrade. My cousin has a HO NOS and I have tried that a few time and think it is AMAZING. What I know I want is an edge to edge concave but I am unsure of the rocker effect on a ski. I am 210 pounds and am riding 28' off and getting shorter so if will have to be 69" or longer. I have found a NOS, a Monza, and a CDX, all 2 year old HO's and at a good price. I would also be open to a Radar but don't know many of the models. So what do you think would work for me and be something I could use to advance my skiing as far as it can. And what effect does the rocker have on a ski. Also I have been looking for a good forum like Wake World but for waterskiing any suggestions.