rear end

Ok after setting my wheels and tires in and measuring backspace to backspace I came up with 50 5/8ths. Now this is about ¾” of clearance from the tire to the frame rail is this enough? I’m trying to get as much on the outside as I can to prevent rubbing. Tire size is 28x13.5 MT ET Streets on a 15x10 mini tubbed Scamp. Rim has a 5.0" backspace