I made mine from 9 guage. Bending it into a circle was not fun.
I used a 5 pound hammer and wore heavy leather gloves to fight it into a loop.
The 9 guage is overkill. I made the base from a Weber charcoal grate, the brunt of the heat and wear are on the bottom, my fire never even touches the sides of the basket.
I am collecting parts for a new UDS build, 13 guage is what I want next time.