Choose your substitute by dish: Israeli couscous or orzo for soups/sauces, ditalini for hearty stews, and tapioca pearls for gluten-free creamy dishes.
Use the listed ratio against your original acini di pepe amount (1:1 for most swaps; 1:2 for pearl tapioca).
Start timing early: cook until just tender, then drain/rinse if you need to stop carryover (especially for salads).
If your swap absorbs more liquid (common with tapioca and couscous), add a splash of broth or water at the end to loosen.
Taste and adjust salt/sauce thickness after cooking so the substitute has the same seasoning intensity as the original pasta.