We have a large propane tank quite a distance from our cabin, the main feed hits the cabin on a 3/4″ iron pipe with t’s. From there extends copper tubing to a couple of things, and flexible pipe,(like an appliance(stove) has) to a couple of others. I need to add an additional line and want to know; SHOULD I USE COPPER TUBING OR FLEXIBLE APPLIANCE LINES? Thank you, Sally