How much ignition advance with WI?

[raddy]

HI
I wonder how much you others usually advance ignition timing with WI? In my car I must advance timing relatively lot to avoid misfiring at max. rpm and load. With less advanced (more retarded) timing I get missfiring at high revs and load (same like with too much retarded ignition and without WI), but it get better and better with advancing ignition timing. Unfortunatelly I dont have timing gun, so I just slightly rotate CAS and listening for detonations...
Im using water/ethanol mixture (25%of ethanol), switched on at 0.7bar, max. boost is 1.2bar, car is nissan 200sx with ca18det engine and T3 turbo.
Im using cooling mist WI kit.