Just a few points that might be worth adding. You didn’t mention it in the post, but the MER’s chart does mention tank ullage pressure (which will be a factor if you’re using a different feed pressure like say for a pressure fed tank). Also, you have to factor in what FOS you’re using on the tank structure.

Also the “scales linearly with volume and pressure” assumption only works really well for larger tanks (ie bigger than the ones we’re working on at MSS), because you have certain structures like the skirts, flanges, sumps, slosh baffles, etc that are more nonlinear. Past a certain size they’re small enough that they’re in the noise, but below a certain size and they start becoming a bigger and bigger fraction of the tank weight. And that’s actually long before you hit actual minimum gage issues.

~Jon