My diffuser is just the former lid from the barrel itself. The rim was cut off to attach to the Weber dome lid and the inner circle of the former lid has a rebar hoop on it so I can grab it out with a turkey hook. It sits directly on top of my charcoal basket, no holes in it, nothing. Seems perfect to me.
PNWBA - Hayden, Idaho http://www.facebook.com/BC2BBQ