Debbie, us plant admins check this forum regularly anyway, so even if you don't call a particular plant admin, one of us will see it (usually within a day).
You cannot use a hybrid formula as the name of a genus. It has to be a valid genus name. Formerly this would have been Mangave, but it looks like Manfreda has been merged into Agave.
So the genus is Agave, the cultivar is Aztec King and the common name would be Mangave.