What does it say on united.com for your PNR or on your e-ticket?
I am still pretty confused by the rules but my understanding is:
Assuming the bags are tagged directly, you would think the IATA Most Significant Carrier (MSC) rule applies. In this case, it would be TG because it crosses the IATA sub-areas. So, TG rules applies for the entire journey.
Maybe UA won't care and let you put through. I have heard people getting charged by the connecting carrier even though they thru-checked their bags.
Then the risk of more money being collected increases if they can't hold your bags for 20 hours. The risk of the bags lost increases if they hold your bag for 20 hours.
Good luck.