GTM iRule to modify Query?

This is what I came up with, and please feel free to improve and post back as my TCL skills are a bit rusty.

when DNS_REQUEST {
       set wip ".wip."
       set in_query [DNS::question name]
       set suffix_query [string trim [domain $in_query 2] " "]
       set lead_domain [string trim [lindex [split $in_query "." ] 0] " "]

       set out_query "$lead_domain$wip$suffix_query"
       log local0. "$out_query"

       cname $out_query
    }