Hondata

what is the max acceptable knock level and what is not acceptable knock level ? between 0-5

ecu w/knock board how manny ign timming it retard wen knock level is high?between 0-20 ign

You should tune it so that there is no knock. When you have it properly tuned you will have no ignition retard from knock. Think of the knock control as a fail safe if you get bad gas.