I like it. There is no reason you have to coil or helix your HX.
I was thinking about your epoxy end fittings. If you wanted to make them serviceable, you could use a standard water tight cord grip or cable gland from the electrical industry. They have plastic and metal versions and they are available with a rubber seal / bushing in the water tight versions. Also, they use standard pipe thread sizes.
Liquid-tite style conduit may be useful in these applications also.