Help with rearend and tires

Whenever you're putting big tires, tubbing, and narrowing a rear, the first thing you do is buy the wheel/tire package you want. Then you measure to determine how wide of a rearend you need. Obviously, you'll have to do the tubbing and moving in of the springs first. Trying to narrow the rear first and then buying wheels and tires can be enough to drive a man to drink. Do it the right way if you're gonna do it.