I use a simple combination (why complicate things?) of "Lawrys Meat Tenderizer", "McCormick Season All" (now "Mortons Season All") seasoned salt, and "Bolner's Fiesta Brand Fajita Seasoning".
Apply a liberal amount and place the meat in the fridge, wrapped in plastic wrap, for about an hour. Take out the meat when firing up the grill.
Fast cook over flame cutting the slab into smaller pieces as this method increases the quick charring of the ends. Cutting the meat into smaller pieces will let the juices run out as the heat quickly cauterizes the ends.
Cook to your doneness preference and slice across the grain for more tender pieces or with the grain for more chewier pieces.
We serve on flour tortillas, warmed on the grill off the flame, with fresh guacamole and cilantro.