That diagram was very helpful. I dropped plumb bobs, put tape on the floor, marked the points and measured between them to make sure everything was Square. I did this after my connectors and braces were welded in. Not the greatest idea. It was reassuring to at least know the dimensions were correct once the frame was level and supported. I had my car on Tire cribs when I weld it in my subframe connectors and the frame horn brace on the front. Thank God I had everything straight when I did my welding or it would have been a catastrophe. I lucked out big-time.