Thanks. My monthly CC spend is $5000 and my credit score is good.

Yes, my concern would be that after 3 years having 400k miles but not being able to secure 4 seats. I would apply this "plan" to whichever airline gave me the best shot (i.e. - BA, Virgin, Star Alliance, etc.)

In my research I believe that a UA reward ticket does allow a stop over or 2 and an open jaw.