I got a stainless steel mixing bowl on Amazon and it fits perfectly Crestware 20-Quart Stainless... https://www.amazon.com/dp/B00857VJ2S?ref=ppx_pop_mob_ap_share it was also 1/3 the price of the OE water bowl from Weber parts depot.
What are your thoughts on it? I have one in my shopping cart at bbqsmokermods.com but I wasn't sure to pull the trigger on it yet or not. I was also considering this.