Just how big is this thing?
45 inches doesn't go very far and I'm having trouble imagining any 'large duffel' comply with the limit.
Does it fit in the standard sizer?
Same goes for aajones, would the bag with the bulge fit in the sizer? Probably not I'd guess.
I know my own carry-on is two inches inside the limit but if I over pack it it is easy to get to a point where it is outside the limit.