Unless you're hung up on a bone-stock buildup, why not step up 1/16" and plumb the line with 1/2" tubing? The end fittings are 1/4" pipe thread, right? It won't hurt to use readily-available pipe-to-flare fittings and adapt the line to 1/2" tubing instead of something that's so hard to find. If you need to drill the flare fittings out for a slightly larger internal diameter, there's plenty of material available to do that without weakening anything.
Jerry
