My cooker has steel grates. 3/4" flat expanded. Stainless is EXPENSIVE! Season the steel grates with cooking oil and high heat. They'll get better with use, unless you wash them with soap & water after every use. (That's not recommended, IMO). Treat the steel grates just like a cast iron fry pan... Cheers!!!
If Homebrew & BBQ aren't the answer, then you're askin' the wrong questions... Cheers!!!