For anyone having an issue getting the quill tight enough to not turn inside of the steerer, I'd suggest one or all of the following (in addition to greasing the threads and wedge):

1. more torque, as noted already. 15 ft*lbs (20 N*m) is fine given the size of the hardware.
2. grease under the top cap where it meets the steerer tube. This interface can generate a lot of friction especially if the steerer tube has been cut and the anodizing is removed.
3. friction paste on the quill portion. The ID of some steerer tubes may be a little more than others requiring more deflection of the quill to get a good 'bite'. The grit in the friction paste will reduce the amount of deflection required while giving more potential grip and helping prevent corrosion.

I do appreciate the feedback and will see if there's something that can be done on future units to improve this function.