FMJ first (sealant) then the wax.
Sealants typically always need to be applied first, to ensure proper bonding with the paint. Sealants will not bond well (if at all) over other waxes, generally, and will hurt durability.
Also, don't know too much about your wax product, but you should make sure its not a cleaner wax, or else it will remove all of the FMJ in the process.