iRule to a variable for chosen pool member

i have more code in the when ACCESS_ACL_ALLOWED.. i am wondering i can move it all to the HTTP_REQUEST_SEND event..

what we have now

when ACCESS_ACL_ALLOWED {
   set user [ACCESS::session data get "session.logon.last.username"]
   set uri [string range [HTTP::uri] 3 end]
   HTTP::header replace "APP_USER" $user
   HTTP::header replace Host "server1.domain.com:8080"
   HTTP::uri $uri
}
when HTTP_RESPONSE {
if { [HTTP::header "Location"] contains "server1" } {
HTTP::header replace Location [string map {"server1.domain.com:8080" "app.example.com/app"} [HTTP::header value Location]] }

}

What i think we need.

when HTTP_REQUEST_SEND {
    if { [class match [LB::server addr] equals prod_servers] } {
        serverside {
            set user [ACCESS::session data get "session.logon.last.username"]
            set uri [string range [HTTP::uri] 3 end]
            HTTP::header replace "APP_USER" $user
            HTTP::header replace Host "[class match -value [LB::server addr] equals prod_servers]:8900"
            HTTP::uri $uri
        }
    }
}
    when HTTP_RESPONSE {
    if { [HTTP::header "Location"] starts_with "prodserver" } {
    HTTP::header replace Location [string map {"[class match -value [LB::server addr] equals prod_servers]:8080" "prod_app.example.com/app"} [HTTP::header value Location]] }
}

What do you think??