Pics of pro-touring Duster with 20s?

The wheel size 17"-20" really isn't as important as the stance of the car once finished, you just can't slap on set of off the shelf wheels and hope for the best. In my opinion the car has to be low...and the tires and possibly some wheel has to be tucked up inside the fender. unfortunately 73'+ front suspension has a wider track, I would invest in a wheel measurement tool and have the wheels you want built (if it's within your budget) to get the correct stance.