Originally Posted by yamawho:
Does the space at the top need a 1 3/8" or 1 3/4" section to fit?
No, it's less than an inch. I don't put anything in there - just snap it together. Video here(NYC SSS traversing reversing loops - slightly elongated in both directions with regular 10" sections to fit the tables - no tiny fitters, just the one 5" half section as per above diagram):