Season roast well with lemon seasoning blend and grill over indirect smoky coals to desired temperature (suggested 120-125 degrees internal) remove, cover and rest for 5-10 minutes and then slice thin across the grain.
While tri tip cooks, combine sauce ingredients and warm gently in a pan or microwave.
Spread a generous spoonful of the sauce on serving platter, transfer sliced roast to plate, drizzling with all the meat drippings. Spoon over remaining sauce to taste.