Don't know anything about the mini, but I love cooking tri tip. I use the same homemade rub (brown sugar, cumin, chili powder, paprika, nutmeg, garlic powder, salt and pepper) I use for ribs and butts. Recently, I have been doing the reverse sear bringing the temp to about 115 before pulling for the sear. Last time I think I used raised indirect at about 275.
After the sear, I cut the tri tip on top of a board sauce. Sauce is simple; olive oil, fresh thyme (dried works too) cilantro, diced jalapeño and a little salt and pepper. Be creative, use flavors you like. Coat each slice in the sauce/juice mixture and enjoy.
Dinner!!! Finished with a simple board sauce; EVOO, thyme, jalepeno, garlic, salt, pepper, and lime (I usually use cilantro, but it was a no show today ). Potatoes could have cooked longer and meat was farther from med rare than I like, but it was all good.