Check the tri-tip for any surface fat or silver skin. Trim off any that you find.
Put meat into zip-top bag with one 16oz bottle of marinade. Remove as much excess air as you can, close bag and toss meat to coat.
Put into fridge to marinate for 1 - 2 hours.
Preheat smoker to steady 250°F and add hardwood.
Remove meat from marinade and pat dry.
Dust surface with dry rub. Press rub into meat with open hand. Let sit at room temperature for 10 - 30 minutes.
Place tri-tip on smoker grate and smoke until internal temperature reaches 110°F.Note: you are smoking the meat to an internal temperature, not for a length of time. Different sizes of meat will cook for different periods.
Remove meat from smoker and tent with foil.
Prepare a grill for direct cooking at 475°F - 500°F - or use a cast-iron skillet over high heat.
Sear the tri-tip on both sides to achieve grill marks and color.
Remove the roast from searing when the internal temperature reaches 125ºF.
Let rest for 10 minutes.
Slice thinly across the grain and serve warm.