The challenge, of course, is that POSSIBLY even if you commit to UA, you may not get GS status. You might consider not worrying about trying to get GS status, but instead develop/maintain top status on UA (or other Star carrier program) as well as one or two other programs (such as AA). Personally, I'd rather have 1K on UA and ExecPlat on AA rather than GS on just UA (or equivalent).
So, you might fly UA sometime and CX sometimes. Maybe CX westbound to enjoy the service and UA eastbound (and just sleep)?