I am posting this here so I don't lose it! This is the first time I got this right - at least the way my MIL and her family makes it. (Note the measurements are still altered by taste: too sour, more soysauce; too salty, more calamansi juice). If you don't have calamansi (a native small lemon that's sweet and sour at the same time), you can try using meyer lemons. Typically my inlaws use london broil, but you can use any cut. One of the methods used to tenderize the tough cut (yet cheap) cut of meat is to pound it. Another hint on handling the meat: Before you slice it, stick it in the freezer for 15-20 minutes so that it is easier to slice thinly.