Great looking food there. TT is a great flavorful cut of beef, and you cooked it perfectly it seems.
I do want to point out that you did slice with the grain, and you want to slice against the grain.
Of course the flavor remains the same you just get a bit more chew to the meat. Try slicing this way next time and I think you will be much happier, if that is possible(which I know it is because I love me some Tri-tip). Cut the red line, and slice the blue lines. There, I just gave you an excuse to have to cook another one.
Carlos