Cover tenderloin, and let stand at room temperature 1 hour.
Meanwhile, soak wood chips in water 30 minutes. Prepare smoker according to manufacturer's directions, bringing internal temperature to 300°; maintain temperature for 15 to 20 minutes.
Pat tenderloin dry; brush with olive oil, and sprinkle with Hill Country Rub.
Drain wood chips, and place on coals. Place tenderloin on cooking grate; cover with smoker lid.
Smoke tenderloin, maintaining temperature inside smoker at 300°, for 45 minutes or until a meat thermometer inserted in thickest portion registers 130°. Let stand at room temperature 30 minutes; cover and chill 12 to 24 hours.
Coat cold cooking grate of grill with cooking spray, and place on grill. Preheat grill to 400° to 450° (high) heat. Place chilled tenderloin on cooking grate, and grill 2 minutes on each side. Let stand 5 minutes before slicing. Serve with Chimichurri Sauce.
Budget-Friendly Steaks Feel free to substitute one of these for the tenderloin. Reduce the rub to 1 1/4 tsp., decrease smoker temp to 250°, and follow smoking times below. Tri-tip steak: 1 1/2 lb. for 20 min. Flank steak: 1 lb. for 15 min.