what length did you go with for the 4x4s?

as i was planning mine, i expected to go with the 8' amazon recommended and strap to the legs, but getting it low enough to strap to the cross beam seems ideal. I'm debating between your set up and going high enough to throw a tarp over the top and be able to stand under it.

also, your connection points don't appear to just be eye bolts what're you using there?