I use Fragola on everything. American made and a huge selection of fittings and hose. Summit carries a large selection of Fragola hose and fittings in stock. I prefer the lite black nylon stuff if you want some added security they sell internal springs for things like oil lines. FWIW I have NEVER run a dual line set up. All three of our current deals are single -16 lines pretty much all I have used for years.