The bottom line is that you
can cook Tri-Tip like a brisket. You could also cook filet and prime rib like a brisket as well. But why bother? Brisket and chucks lend themselves to long slow cooks due to their inherent toughness where a long cook time can break down their tough meat fibers, not to mention high fat content that provides a juicy finished product that's not possible with Tri-tips and other tender cuts.
Typical California Tri-Tip is most often cooked over red oak and seared first over high heat, then finished over indirect. I prefer reverse searing, and you can read more about that
HERE.
To answer your question, how long it takes depends on what your temp is. For the first and indirect part of my cook, I usually am working with a temp of around 300-325, so for a 2-3 lb Tri-Tip, it usually takes about 40-50 mins total cook time. Looks like you have a Weber kettle, so that would be the perfect unit to utilize for a reverse sear and at the temp I mentioned. If you want your meat medium rare, I'd be looking at moving the meat to the hot side when it reaches around 110 degrees, and pull when it hits 125. By the time it's rested, the internal temp should be upwards of 130-135, which is the medium rare zone.
There's another factor that determines the outcome, and that's the quality of the meat. Now matter how perfectly you cook a piece of meat, there can be a wide margin of difference between select vs choice, or even choice vs prime. I don't mind spending a few extra dollars for choice or especially prime when I can get it because I know it will make a huge difference on the plate
and palate.
So TT will dry out if cooked like a brisket......bummer. Maybe I didn't have a good one but the one I tried before wasn't that great cooked like a steak. I must have misunderstood.......I thought the classic, old school California style TT was cooked low and slow, no? If not, how is it done?
Also, if I smoke to 120F and then reverse sear to 130F, roughly how long does thus take so I can plan a cook for dinner?