It's 6pm July 2nd where I am, and the website says there's 23 hours to go. So 50-90 July 4th is actually July 3rd at 5pm Pacific?
Technically you are supposed to wait to start until it is July 4 in your time zone, but the site will unlock based on the international date line. That's why it starts early.
According to the FAQ, the site unlocks at the end of July 4 at the international date line, which (as stated in the FAQ) is 7am Eastern on July 4 (or 4 am Pacific). But as you note, that's not what the countdown clock on the front page says (it says 8pm Eastern on July 3rd, which is still July 4 at the IDL). I suspect the countdown clock is off, but @Eric Distad can confirm one way or the other.
The problem with waiting until Jul 4th in my time zone is that 50-90 would end before it was midnight on Oct1st my time... I think
I think the site also stays open until it is not longer Septmeber 30 anywhere in the world. That's how it's worked in the past.
Yep, I thnk Val is correct
Opens as early and closes as late as possible seems fairest to the largest number of participants to me.