I created a responsive template for a monthly newsletter last month that was full-width in Gmail app by some stroke of luck, but due to it being edited and slightly redesigned in a WYSIWYG editor, I decided to re-make a clean copy with the final design.

Everything looks good, but where the previous template was full-width, the new template has the evil Gmail app margins on iOS (narrow on left, larger on right) and Android (broad on both sides).

I've pored over every Gmail width fix, but none seem to be making any difference at all to my e-mails. It's almost as if I am not changing anything at all. I tried adding min-width to all tables and images--nothing. I tried Michael Muscat's fix here. I tried several other fixes, and nothing changes.

It's possible that I don't understand how to fully implement these fixes because they were only discussed without any real guide. Can anybody walk me through how to correct these full-width issues with the "min-width" fix?

Thanks.

EDIT:
Additional details--I am using a highly modified version of Nicole Merlin's Future-Proof Responsive Email, if that helps.