The Hunt For Big Fish with Larry Dahlberg

When you are making your form to produce replica marlin heads what kind of tubing are you inserting in the leader hole when pouring? I recently bought a bunch of kits to start trying to make my own but im having a hard time figuring out what to use for this.

Thanks

Ive used everything from brass, aluminum, plastic tubing from various straws, swabs from dr. office, regular tubing from hobby store used model airplane engines, ..can also combine with pop rivets removed from their pegs as an anti chaffing measure if needed.
are you using a pressure pot and clear alumilite or are you using amazing clear cast?
best
L