Biggest tires for mini tubbed Duster

When I mini tubed my Barracuda, I found that tread widht wasn't the only thing to look at. Many tire companies can give you the section witdth on a tire. That can effect what fits more than tread width. So what I did was found what the measurements were in the wheel well. Springs to fender out side etc. I also measured from the center of the rearend to the front and rear of openings. Once I had kind of a 3D drawing made from all the measurements I went out and found a tire with measurements that would fit in there. I also found out where the the rear end wheel mounting surface was located and figured out what back spacing to use. That way I could center a large rim in the center of the well opening. My mini tub job on my Barracuda I put the springs in line with the frame rails and I was able to get a 11.5 x 29.5 x 15 Phenoix slicks into my openings. Good luck getting big ones in there.