CVG is the DHL hub in the US. Virtually all international traffic goes through the sort there. HKG is obviously a good hub for SE Asia; maybe BAH is cheaper than DXB for the Middle East...
Someone else has already provided you with the numbers you were looking for, trust that settles any doubts you had on the payload/range capability of the aircraft.
As for the above, it sounds as if the information you have does not reflect the actual world. Some of DHL's international traffic does indeed go through CVG, but instead of being "virtually all" it's rather "a pretty small part". As for choosing BAH over DXB it could of course have to do with cost. It could also be because BAH is where DHL have their Middle East freight ce ntre, just like HKG is where they have their main Asian ditto.