It took a couple of tries to get the flare correct, and to figure out how to weld in the inner sleeve that keeps the "donut" gasket aligned. Basically it comes down to using a fairly short section of tube, (+/- 2") with both ends cut exactly square to get a symmetrical flare, and then pressing in the sleeve and welding it from the inside on the downstream end so the heat of welding doesn't distort the flare. Dealing with stainless tube is much trickier than mild steel, particularly but welding the pie sections to make the curves.
