We do tri-tip all the time on the grill here in So Cal. However rather than a rub, we do a garlic paste (rough idea of recipe below) and marinate the meat in it for at least 4 hours, but usually overnight. Then we sear it over hot coals and move it for indirect heat and add some soaked Red Oak Chips to the coals for the smoke. Take it off at 145, tent it and let it rest for 30 mins before cutting.
The above works great, but I plan to get the Cookshack involved this next time - where we will smoke it in SM025 first and then finish it on the grill. Question: Could you first sear it then finish it in the CS?.
I ordered some California Red Oak Chunks from here:
http://www.fruitawoodchunks.com/redoak.htmlSanta Maria Marinade for Tri-Tip 1-2 Heads of garlic pealed
TB Kosher Salt (tablespoon)
TB Fresh Cracked Pepper
1/4 c Olive Oil
2 TB Fresh Rosemary (not traditional, but I add it)
Throw the above in a small food processor and combine to make a paste. Stick the tri-tip in a large ziplock and add the marinade. Marinate for at least 4 hours (overnight OK), let it come up to temp out of the fridge for an hour or so, then start cooking.
To serve, we cut it against the grain fairly thin and put it on a long soft roll and then finish it like a pulled pork sammy... a little coleslaw and your favorite BBQ sauce.