All right, I'm going to give you all one of my biggest secrets here...
Go to Rosenthal and buy a marinated tri-tip. It comes shrinkwrapped in the heavy plastic. Get a nice hot fire on your grill and sear it on both sides, then move it off the direct heat and use your instant read thermometer until it's done to your liking. (Medium rare for the Tailgate family!) Pull it off, let it rest for five minutes or so, and slice it thin against the grain. You can thank me later.