I have been back and forth to the US at least 16 times on Emirates over the last four years. Check the loads and pick accordingly. Yes I have not been on several flights that I thought I would have been and I have hauled myself and my luggage to an Airport hotel and successfully gotten on a flight the following day. Yes I have had to pay several dollars to change confirmed US flights to another day. HOWEVER, a 14 week profit sharing check way exceeded monies I was out attempting to non rev. If you have to be somewhere, May I suggest you buy a real ticket.
Also use your ALT wisely. If you are planning to be somewhere else besides Dubai in the summer, thats probably the time when you need your ALT and use subload A's or Cat C at less traveled times of the year.