The Point Guy has a good post about this - http://thepointsguy.com/2012/06/maxi...-domestically/

I followed his advice for some transcon redeyes where getting the upgrade was important and hard. In each case I was #1 on the upgrade list out of 30+ and got 1 of 2 seats. Several of the skyclub reps did not even know how it worked - I was confused about the fact that I was checked in for the confirmed seat but not for the waitlisted SWU seat and they could not help.