hey dude, its not actually that small compared to the others if you look at their middle numbers (other than the NS). When those boards list the 3 numbers its really only the very ends of the sidecut that open up into the bigger radius, the reason they do that is to make the ends of the board a bit less catchy and grabby which helps the board act more stable at higher speeds
what rome does instead is makes a very mellow transition zone (the part of the board where the sidecut starts to blend into the nose curve in both directions- up off the snow and around the tip), if you detune this area as well it results in the same kind of behavior as having a tri radial sidecut. some people would argue that the reason why companies use the tri radius method is that its easier to engineer than a variable zone transition zone, some would argue the other way.
so in my opinion you don't have to worry about the flag washing out or anything, its more a matter of adjusting your technique anyway to find the sweet spot on the board, people are way to quick to blame the specs of the board or the "tech" for any percieved lack of performance. when you say is it "going to take high speed turns as well" its sort of a dead end question. it implies the other boards you listed are automatically better at that just because their specs supposedly say they will be better, but as you know, the way a board behaves is the result of a combination of all its specs/tech, not just one attribute (in this case:sidecut radii)
all the manufacturers that you listed make good products, i doubt you would be disappointed in the flag.