What determines which nozzles are used by the H2C? Is it determined by the printer, or is it something I need to set somewhere?
Do you mean which physical nozzle from the induction nozzle rack gets used if there are multiples of the same size & flow type?
You can select which filament (or color) gets mapped to which physical nozzle when sending a print to the printer (at least in Studio and on the printer itself, I never used the Handy app).
On the printer it looks like this: https://wiki.bambulab.com/en/h2c/manual/h2c-firmware-release-history#h-01010000
The Studio options are shown in the wiki, if you scroll down a bit from here there’s an animation showing nozzle selection for the right side colors.
https://wiki.bambulab.com/en/software/bambu-studio/multi-color-printing#ams-mapping
HTH,
-Max
That’s the info needed to know, thanks!