I have a BX 2380 and a Ford 1720 4WD. Is there an auger that will work on both? Is the BX to small to worry about an auger on it? I am interested in a 9” & 12” bit. But I can take the BX through the yard not worry about tearing up things.
You might reconsider augers so close in diameter. A 12" and a 6" might prove more useful depending on your purposes.
I use a 12" for posts which are concreted-in or for planting shrubs/trees/etc. because the concrete adds weight and the bigger the hole the more grip.
But a 9" hole for a pipe or fence post that won't be anchored with concrete only means a loose installation requiring filling/rock/tamping/etc, while a smaller hole makes a firmer hold with less of that.