I use foil
Not that I'm anything to go by but every single brew for the last year of so so over 30 brews easy have either sat in the kettle to chill overnight or sat in the fermenter to cool down until tomorrow.
Zero infections at all.
Just pop some alfoil on top I do then the lid.
You wanna use it again turn it over
Amen man you do what works for you with what you've got at your disposal.I tried a few overnight cools and it scared me, but I know you guys in hot climates where water is an issue have it down to something of an art. The - slight - possibility of (particularly botulism) infection spooked me pretty good.