Thanks!
I don't have any without the cans on right now but I used the
Rotopax universal mounting plate which I drilled 4 new holes into, to mount onto the screws that are already on the tailgate from the tire carrier. Ive seen other people put nutserts into their tailgate to mount it using the holes already drilled in the plate, but I figured I'd rather drill holes into the plate than even more into the Jeep (and I hate doing nutserts).
I need a better way of mounting the license plate onto the cans though. Right now I'm using nasa space age technology to hold it on there (velcro and zipties) but I'd like something more permanent.