Horizontal stabiliser question.

[Shay King]

On page 1 of the plans the innermost rib on the stabiliser has the note ‘Flat side’.
Does that mean that rib is on its side, whereas the other two are sharp sides down?
Also, the tubing between the gussets for the 3/16” bolts, what are builders using there. Is it 3/16” inner diameter bushing material or aluminium tubing with a loose fit?

[Kamcoman77]

Inner rib, opening goes toward outer tip, other ribs, opening goes toward inside end. I used aluminum tubing with 3/16" ID for my brace wire gusset supports. I used JB-Weld to epoxy them in place. So did my pal who is building his own XL in my shop.