Basically two ways with Tri-tips. Med-rare or all the way like a brisket. Personally, I go with a reverse sear. Smoking them to approx 120º, pull and let rest to stop the cooking action then place on a very hot grill to sear both sides and increase the IT to 132º ish. Pull and let rest for 10 minutes before slicing and the IT should rise a couple of degrees to ~135º. We find that a final IT of 130º is a bit too much on the rare side for us.
Here is a view that I believe
clifish
provided a while back on how to approach the slicing when done.
View attachment 689046