Almost always 0.4 (sometimes 0.4 stainless). It is the biggest one that still gives me acceptable tolerances, and printing time is easier to deal with than imprecise parts.
Changing the nozzle and recalibrating feels like too much of a hassle for me, so I didn’t experiment much though.
Food grade stuff. Cookie cutters, spares for cat drinking fountain. I guess hardened could’ve worked too. Printed with ColorFabb HT, so it can just go to dishwasher.