Material isn't as important as design, applied force and safety factor. For most structures, a 1.5X safety factor vs. maximum load (hard bump at full speed) is used, 2X for composite structures. For safety critical items this goes up. On the Fossett LSR, we use between a 4X and 20X safety factor on primary safety items like the parachutes and brake.
Since this is a handle that you will pull on, potentially when some thing is going badly wrong, it should be stronger than you are regardless of what it's pulling on besides you. For a seated person, a one handed pull limits out at 75 to 250 lb. depending on the person. If the handle can take a 1000 lb pull without bending, it's probably OK. So build it and hang some serious weight on it.
This sounds crazy, but a P-38 pilot once dove too hard and ended up pulling out with both hands on the stick and his feet on the dash. The stick bent at 2200 lb. The stick bent, didn't break, and he made it. So that's the standard for controls.