If you have a rack then your lighter items can go up there. Center of gravity wouldn't be affected as much as it would with six jerry cans. In the desert you'd likely want some form of container to keep the dust out, especially if the light items are your clothes and sleeping gear.
Without a rack then the competing interests of six jerry cans and the rest of your gear will require you to evaluate what has to go and what can be left home.
Without a rack then the competing interests of six jerry cans and the rest of your gear will require you to evaluate what has to go and what can be left home.