Footer Blocks – different width columns?

I’m trying to get the footer blocks to have different widths.

The Theme Settings > Footer Layouts teasingly show different widths, but alas they are actually all the same class as far as I can tell.

any tricks to having different widths for footer columns? (ie. 20% 60% 20%, or 20% 20% 20% 40%, etc)

I’d like to avoid using html in a text widget

thanks