I haven't personally used dyna liner, but if it is was I think it is, you cannot spray a liner over it bc it is a foam product. The best results I have had is with dynamat, and spray liner! It dampens sound and vibrations. I am not a fan of herculiner, even with proper prep it has a tendency of chipping. If you do it use a two stage with a base and catalyst, this is a stronger product and if installed properly won't chip!
"Someone once told me not to bite off more than I can chew, I told them I'd rather choke on greatness than nibble on mediocrity!!!"