If you have difficulty finding or identifying tri-tip in your area, just ask your
butcher for a NAMP 185C
cut. It's admittedly hard to find east of the
Mississippi, but it's well worth your effort.
Next, you want to cook tri-tip like a big ol' steak. Smoking is not your
friend with this cut. Use what I call a "Red Neck Sous Vide" method, which
is also known as "reverse sear". Cook the roast indirect until it hits about
110* internal, then sear it over direct heat (400-500*) for about three
minutes per side, to a finished temp of about 125-130*. You're looking for
a beautifully dark, but not charred crust.
Let the roast rest for at least 10 minutes, and then cut it across the grain
1/8" to 1/4" thick.
All you need for seasoning is kosher salt, fresh ground black pepper, and a
little granulated garlic.