Do you have any Z1?
If so, a good Z7 or any car shampoo will remove any carnauba products that has been exposed to the environment for more than a week or two.
Use Z1 and work into surface. Z1 is not only a great product for the secure adhersion of Z polishes to the surface, but many forget that Z1, which most view as only a pre-cleaner, really adds to the wetness (depth) appearance of Zaino polishes. Z1 wil not remove firmly attached previous layers of Z.
The important step is to "work" the Z1 into surface to the point that even a slight haze is too much product remaining on the finish. By using this Z1 application method, the drying time of the immediately apply Z2 or Z5 will not be greatly lenghtened (~1hr total).
Z7 wash and Z1 pre-treatment of the surface works great for removing residual oils from toppers.
Yes, you are limited to only one layer of Z polish for this session, but you may discover that topping now is not necessary. Next weekend use your ZFX and add 2-3 more coats and plan to be bored for the next fews months with just washing and Z6 Qd'ing. :xyxthumbs
This conclusion is applicable only if your previous prep produced the "natural" wetess and depth of your finish. If not, a carnauba topper will alter the optics and produce of this appearance.