Hey Jody, I'll answer here today rather than in a PM. My fresh water tanks are 3/16" and as you noted they have baffles. The baffles dissipate the tsunami that occurs in the tank if the bus stops suddenly. They will help keep the tank from lifting at the rear and pitching forward. My interior tanks are caged in angle iron on all sides with the cage bolted or welded to the floor. While I'm thinking about it, accept nothing less than spin welded fittings on your tanks--they will last the lifetime of the tank without failure. Both glued and compression fittings will eventually give up the ghost. Best practice is to support the entire bottom of the tank.
My black tank was (in the fifth wheel it came out of) supported only by a lip on the upper edge of the tank. Though the tank was only 5 years old, the bottom was definitely sagging. I added steel strap supports on the underside and while they are working a full floor would have been better I expect.
Jack
In this pic I'm still completing the tank cage which eventually surrounded the entire tank. The cage also served to support the stove and oven.
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This is a pic of the support I built for the black tank.