Tygon has a very low melting point making it a POOR if not dangerous choice for glow fuel lines.

It melts quite easily when in contact with a glow engine, where silicon does not.

( heck I wish we had a better alternative to Tygon for gas lines, as I've lost a plane due to brief contact of a vent line with a muffler exhaust tube. ).

I've seen gas melt glow fittings in a matter of a week, and glow melt gas fittings in equal time.

There is a reason we do not interchange these things.