I recently upgraded my NS F2004's 5.4m to 11.9m (which I loved) to F2006 5m to 11m (which I hated at first). They also felt very physical CW the F2004. After getting some advise from NS racers/speedsteers, it turns out that all sizes need alot more down- haul. I'm now using the "max dot" on the VTS as its "min" set and going about 4cm past the "min" for max, does that make sense? Sails now feel lighter, cams rotate better (but not perfectly) but still feels taught in a good way. If you use a 490 mast, the sail will be very flat & might feel a bit gut-less. CE will move back sooner in gusts as well. I could be wrong, so it might be worth trying if you have a 490. But it does sound like under downhaul is the problem.