I thought I'd post these here so the threads don't get too unweildly.
This is the Dwyer boom fitting after some judicious filing. As it turns out they don't just slide into our extrusions. Next on the list is to mold an epoxy "T" that will be inverted and glued inside to (hopefully) make up for the material that I removed. Probably unnecessary but it's winter and what else is there to do?