Not sure mate,just using a breaker bar & socket...i know every time i nip them up i do them as tight as possible,if i went any harder i reckon i could snap a wheel stud,so there pretty tight.
i checked em again yesterday and the were still as tight as a drum,now i'm thinking that maybe with these type/style of wheel nuts they need a second tighten after a couple of 100km's after fitting,or maybe it's just my setup.
hopefully someone thats used or using similar lightweight alloy wheelnuts can confirm my theory or squash it. ;)
Rule number one with wheel nuts of any kind - always torque them up with a torque wrench if possible. For steel wheel nuts, it should be roughly 100Nm (alloy ones might be more or less).
Rule number two with wheel nuts is to always re-torque them after a short period of driving, as when you initially torque them they haven't gone through a proper load cycle.