Weren’t they just discussing blocking out the sun..?

You’re certainly on the right track. I only cold brew occasionally, but almost always use 1:6 coffee to water and dilute 1:2 afterward with either ice or hot water, depending on my preference. It’s also what I use when expecting overnight houseguests. Start with 1:8 or 1:6 and experiment thereupon if you feel up for it.

For an indulgent treat, add sweetened condensed milk!