The problem with AUX fan (compared to part fan) is that it is fixed in position and direction. I just had a larger print that failed, because part has warped (detached from the bed) - it became too cold in one side of the bed.
So, AUX fan is something that you won’t be able to fix to certain value but perhaps adjust considering the print size, orientation.
Regarding brands of filaments, I have tested so far.
Almost same settings (temp 265, aux on, part fan low, all have around 0.05 PA and max volumetric speed 20):
- Prusa
- Overture
- Polylite
- eSun
- Extrudr
High temp PETG (temp 280, aux on, part fan low, 0.05 PA, volumetric speed 16):
- Spectrum HT (benchy came out quite OK, considering having some issues with sticking to the bed and had to have 110 C bed temp for it):
The only PETG filament that just didn’t play balls and was always getting crumbling when printing is Colorfabb XT Blue.