Originally Posted by LukeRB

I'd suggest separating 2 pax onto 1 PNR and then keeping one pax on your PNR. That will give you equal chances of getting upgraded until T-24. If you're not CPU'd by T-24, you may want to split your PNR to increase likelihood of you getting a CPU inside 24 hours or at the gate (in the case that only one seat opens up).