Not sure if it will help as there are a lot more knowledgeable/experienced guys here than me, but I put my Duster on jackstands and covered under the wheel well with masking tape. Then started plumb bobbing and marking everything. Flanges, springs, fender lips, etc. i could then measure on the floor exactly what I needed.
Depends entirely on the backspace of the wheel, what bolt pattern/brakes you're running, and how averse you are to fender modifications. In general, barracuda's don't do well with anything that approaches 26" tall in the front without modifications to the lower front corner of the fender opening. But where the wheel sits inside the fender has a lot to do with that as well.