Here are just a couple that I use in my 22"WSM and Weber/Cajun Bandit/Performer
Stainless steel perf.
Holds equivalent amount as the 18"WSM ring
This is one is even smaller-great for 4-6 hour cooks
An expando ring
An 11" ring from a steel container
An expando ring on a SJS charcoal grate.
6"x6" perf steel cube basket in a 15 gallon Mini UDS
Go for it!