It varies wildly from station to station, of course, but I've generally had very good luck with international F bag delivery priority, far better than int'l C or domestic F. At many stations (e.g., SYD comes to mind) there is a CSR who is specifically tasked with finding and removing F bags from the belt and placing them all in one centralized position on the floor, with the goal of getting them there before you. GOod luck!