When I do a tri tip, I marinade for an hour or so with a peppery/salty blend. Take it out throw a rub on it and cook indirect at about 225 for an hour or so with whatever wood chunks you prefer. Then sear it over hot coals for a minute or 2 a side. Turns out fantastic. Never much leftovers. Reminds me of sous vide only you get that great smoke flavor.