I make a sauce using equal amounts of sweet chilli, kecap manis, and light soy (or fish sauce if you have fish), a sprinkle of sugar and about half a juicy lime. Then I taste it and add more lime or whatever I want a bit extra of. Then usually a dilute it with a bit of water but I wouldn't if you are making it ahead of time. We usually use tofu but you can use the same sauce as a marinade before you add the lime juice in.