Either, or. Check the R-value rating as one may be more than the other. Even if you cover it with blown-in, add the important vapor barrier after wrapping to prevent condensation on/in the wrapped insulation while using the AC and the attic is hot/moist. They sell a fiber reinforced tape for hanging ducting (flex- though it won't cut/crush yours), check locally- code here requires R-7 through non-insulated spaces, more is better...
Gary
Gary
