The only real adj in the rear you can do is camber, and you would have to remove the strut and install a camber kit, or drill out the holes so you can adj camber since its a straight axle. There is no caster or toe adj in the rear. If the alignment was out a ton in the rear then it was prob in a accident or something and to fix that you would have to bring it to a body shop. For your alignment in the front, there is so many things that would throw it out in a year. It doesn't really matter what the size of the tires are, when you do the alignment it will put it in spec regardless the size of the tire as long as its not a extreme difference. I would bring it to another alignment shop for a 2nd opinion.