Those are good points, adding material along the bottom would depend on tire size, however one could shim the wheel on the carrier,to a degree for some added clearance.I thought of gussets in the corners for added strength, however with 3/16” steel I don’t think that would be a factor for gas cans. However, if someone wanted to say make it a high lift jack mount, either with or without rotopax, that might be an option.
I could add more material along the bottom, not on the inside but on the outter edge I could.

the mounting spot for the rotopax is below the center line of the bracket, so if reversed unchanged the cans would sit higher

The reason I want the rotopax on the rear gate is to optimize space, saving room on the roof rack for other items. I do off-road frequently, I also camp and fish, so having the extra space is nice. The ladder is functional, throwing the spare up there will take up much of the roof rack. It would make the vehicle even more top heavy for off roading, and won’t fit in my garage with the added height.
Others may want a mount for the same reasons, or for those who don’t have a roof rack.

You can fit 2x2 gallons just saying. I have been in situations where I’ve needed gas miles from nowhere, fuel for boat, quad etc....I also have one for water, good for camping or if the vehicle overheats while in the middle of nowhere off roading.
I’m not trying to make a quick buck selling them, I’d sell them as cheap as I possibly could. I figured since I’m making one for my own vehicle it might be feasible to make others for those “wanting” one. I looked for other options for the h3 and there isn’t anything out there, considering it’s a discontinued limited production vehicle. Yes you could modify a Jeep behind the tire mount, but that’s not what I wanted, if I was to utilize behind the tire I would use that for my hi lift jack.
I thought I’d offer something aftermarket where there is none.
if you want one great if not, that’s great too.