Hardware path
Plan abrasive filament around the nozzle path
PETG-CF keeps PETG as the base polymer and adds abrasive carbon fiber. Treat the property tradeoff and nozzle selection as one planning decision.
Match the material to the design requirement
Start with the base polymer. In this path, both choices use PETG: PETG-CF adds carbon fiber when higher stiffness and dimensional stability are meaningful requirements. Plain PETG remains the more direct route when it already meets the job, and the referenced PETG-CF route has lower toughness than plain PETG.
Check the nozzle before the spool
Carbon fiber makes this route abrasive and changes the nozzle requirement. Make the hardened-nozzle check visible before a material purchase and before creating a new filament profile.
Carry the hardware choice into calibration
Nozzle and filament selection belong in the same saved setup path. Start from the material profile and calibrate the selected combination for the printer.