I would highly recommend, if you haven’t already made this project, to use something other than metal. I have a full functioning slime blower with a Jupiter Electronics light kit and full sound. It’s mostly made from PVC and a Cardboard Sono Tube and it’s heavy already. Metel, I am afraid, would make it worse.
I’d recommend either scaling your own photos to find measurements, or waiting for this guy to finish his plans, as none of the other ones currently on this site are accurate. http://www.gbfans.com/community/viewtopic.php?f=6&t=33678