At my former job, we used to have all of our stainless and high pressure tube and hose work done to spec by a hose shop. If they messed it up, it was their buck. That way, we always got the stuff done right, and didn't waste a lot of money and time doing it ourselves, and taking a chance - a likely one - on blowing a line from us making a mistake. I know; money, pride in the job, and all of the rest of that stuff, but sometimes, it is more prudent to pay the pro.