Some folks will tell you bring it up slowly and reverse sear. Yes, it can be done that way, but its very easy to overshoot, IMHO.
I'm of the camp where you go hot sear on the SNS first, then move indirect to finish it. Aim for about 127-128 in the thickest part of the tri tip. That should be close to medium rare after the rest. The tips will be more toward well. Treat it like a steak and not like a brisket. Hot to start and let it come up where you want it.
That TX rub is an excellent choice. Use a little EVOO as a binder. Add some garlic and a pinch of rosemary to the TX if you have it. There are a couple more tricks and nuances, but that should get you started.
The most important thing about tri tip is how you cut it. Sometimes the grain stays the same direction and sometimes it curves. There is a graphic floating around on how to do it. Cut it cross grain. If you cut it with the grain and then slice it that way it will be super chewy. Sometimes you have to turn the meat, not your knife.
Good luck! You've got this!