Dragonair SO recruitment is something I know very little about. I know they certainly don't take foreigners unless its DEFO or DEC.
What I have heard is that most people try Dragonair first and then have a go at CX if they are don't make it. I have no way to verify this though. I just wondered why you would be an SO at CX for anything up to 4 years when at Dragonair your flying in the RHS an awful lot sooner. Is it that CX are long haul maybe?