The attempt I made last week produced the right flavors, but it was not as
crisp as I'd hoped, and it was a little grainy.

Grainy is probably the semolina, don't add it to the mix, just use it to
dust the breads with and to prevent them from sticking (I regularly leave it
out of recipes because it is so difficult to get here (UK). Crispiness is
often dictated by the amount of water, both in the recipe and as vapour in
the oven. Try increasing the water in the dough and putting a dish of water
at the bottom of the oven whilst heating it up and during cooking. Happy
baking.