I carried two 5 gallon jerry cans for years since gas stations are far apart in the deserts I wheel in. Plus it's too hard to replace the OE 19 gallon tank with something larger. The spare tire carrier I bought from Off-Road Fabricators in Arizona was made to carry two 5 gallon jerry cans down low which kept the center-of-gravity low. The jerry cans were held by the OR-Fab carrier between the rear tail gate and spare tire.
Click on ORF Spare tire & jerry can carriers
. I installed their 85201BB on my '97 TJ and after that was stolen & I bought another and installed it onto my replacement '04 Rubicon. It's a great carrier, my first one never sagged or rattled in the 8-9 years I had it installed and carrying a 35" spare plus two usually full jerry cans. It is stout and well designed.