Once I had the design tool in the ballpark, I installed strings on the truck to be able to take precise measurements. This is necessary to get the axle mounted squarely in the truck. I set the truck on jack stands and squared the frame to the ground, as well. Not having a frame table, I used the ground as a reference point for taking measurements. Knowing the garage floor isn't perfectly flat or level, I always doubled checked side to side measurements with references on the frame.