For dry aging and not the charcutrie the company offers 3 sizes of bags. Smallest is 10×20 suited for a roast for instance; the 12×24 is for ribeyes and strips; and the 16×28 is for brisket and short loins.
But before I go further I need to know if your refrigerator is a modern frost free unit in proper operating order. If not they really don’t recommend trying. Also when you say small then it’s important that the bagged meat will be resting on a wire rack so there is good space above and below, but the ends as well so there is proper air circulation.