from what i can remember working for FDX all DGR bar class 9 are loaded in the two forward positions, with class 5 separated from the likes of class 3/4. saying that certain DGR could be loaded as IDG rather than ADG cannot remember what class/UN number though.
each uld would then be labeled with the amount&quantity of DGR loaded onto the pallet/container,we would then input the amount of DGR into the W&B system which would then be sent to the next ramp/hub.