OAG, for "zero wheel" you do not specifiy the bank angle. Remember that lateral control input generates a rolling moment (either to generate a roll rate or to oppose another rolling moment, for instance that caused by sideslip due to lateral static stability) and does not directly generate a bank angle. I agree with what you say about using a rudder input that results in zero wheel, but you also need 5 deg of bank towards the live engine as this will always result in less sideslip (and hence less drag) than wings level. Note that all FAR 25 and JAR 25 asymmetric performance certification allows this bank angle. Therefore, if wings level you may not get the minimum scheduled performance climb gradients.