Like many rebuilders and repairmen (and repairwomen), I always try
to install original-type materials whenever possible.  As a result,
I often have to cross industries to find these parts and materials.
In regards to twill covered tubing, here's what I've found.

The marine industry uses twill covered tubing for numerous applications,
and recently I've been buying all of my 'one-inch-and-over' tubing sizes
from a local auto-marine outlet that's just a short distance from my
home.  Admittedly, the tubing is very expensive, but it is excellent
quality and the wall thickness is quite reasonable, averaging just about
1/8".  The store I use has been able to purchase any size I need from
one inch on up, in minimum three-foot lengths.

The store also carries, or can get, smaller I.D. tubing, but I've found
that the twill covered tubing PPCo now carries is the same quality but
less expensive.  So for anything under one inch, I buy from PPCo.
Although I may be mistaken, I think Schaff also buys their twill
covered tubing from PPCo.

Regarding large I.D. neoprene tubing, over one inch size, I found that
the wall thickness was a bit difficult to work with when dealing with
lengths of less than six inches.  It just didn't have the flexibility
that I desired, and I found myself having to force the tubing into
position or find other ways to connect the two devices first and then
mount, or move them into their correct location/s.  That's what
prompted me to go looking elsewhere for good twill covered tubing.
I've never liked the attitude, "If it don't fit, don't force it, get
a bigger hammer"..... ;-)

Musically,

John A. Tuttle