There are around 4.5 ounces in one dry cup of ingredients.
So if you have 12 ounces of dry ingredients such as 12 ounces of flour that would mean that you would have roughly 2 and 1/2 cups in 12 oz dry.
So if you have something such as a recipe that calls for 12 oz dry ingredients then you would need around 2 and 1/2 cups that are 8 ounces in size.
Dry ounces can be more confusing than wet ounces.
Dry ounces is more measured in weight and it's easier for most people to figure out the lbs in weight when measuring dry ounces.
But you certainly can measure it in dry ounces as well.