I too am in the same boat on the choice benefits. My question is the following, related to timing on the GUCs:
I am DM for 2018, but I suspect I may only make PM for 2019 (my tix are paid by US gov't, so no biz class). If I select the GUCs this year, and carryover them over into part of 2019, do the chances of them clearing while I am a PM diminish, relative to someone who is using them as a DM? Hope that is not too confusing.