When buying the arrachera at a Mexican grocery store, ask for it to be run through the machine. It tenderizes the meat. You may have to try the recipe a few times to get the amount of seasoning right for your family. Some of my family members also add a 1/2 teaspoon of garlic powder (or 1 clove minced garlic) and fresh cilantro to the marinade.
Nutrition data for this recipe includes the full amount of marinade ingredients. The actual amount of marinade consumed will vary.