Wesley, Many commercial installations are glue-down, with no padding at all. But, to add just a little cushion for an enhanced feel should be done with a thin, fiber pad (years ago it was always referred to as "hair pad," as it was mostly made from horse hair). Not familiar with all the brands available today, but one is called "Quiet Walk;" it or the equivalent will be well-suited to your needs.
Steer clear of rebond or any sponge rubber type pads for this type of installation; they will allow the carpeting to easily loose stretch and begin wrinkling in high traffic areas. Good luck with your venture!