The above tires have a 11.10" section width and by my calculations with the above wheel the tire would extend inboard from the axle mounting point 2.05". I'm thinking that this might be 1" too much and will have to get a smaller wheel/tire combo or a different wheel with less backspacing but I'm not sure without mocking one up, which I don't have. Is my math right and what is the max backspacing for a 73 Duster?