Tube Fly Vise
I've found a trick that works for me when tying tubes using my Nor-Vise Tube attachment;
if using a metal tube, slip the joining(hook holding)tube onto the tube and pinch it against the inside of the tying head by tightening the screw against the mandrel.
The same holds true for the plastic tubes, only insert about 1/8-3/16 inch inside the tube head and tighten the screw against the mandrel, allowing much more of the tube to be covered by material.
There are several jaw held tube tying adapters out there. Having tried them with my Nor-Vise they offset the tube quite a ways from the centerline.
This is much less a problem in a non-rotary, or a rotary vise with an adjustment.
Fishing is serious fun!