On Sunday, when we all submit our wishlists, we'll wind up in a big queue, with it telling us that we are at position X.

If I edit my wishlist while in the queue and resubmit it, do I retain my position, or do I go back in at the bottom?

Pretty sure you lose your place in line.   Hit submit and walk away.   If you even look at the queue screen funny it will dump you a thousand spots.

This is the first I've herd that there is so sort of wait. I thought that when you pressed the button at noon EST on May 19th your wish list was immediately processed. And then you paid for what you got. 
What is there to wait for?
thx. This is my first time. 

The wait is just to go through the thousands of lists that could have anywhere between 1 to 100 some odd events on it.  The processing of the lists begins at noon.  It takes time to work through all the lists.  The line typically processes pretty fast.

After it processes, you will have time to remove tickets, or add more.  If you want to add more tickets before the entire line is done processing, you will need to add them to your wishlist and resubmit the wishlist.

Everyone is going to hit the submit button at noon, it takes a while to go through all the lists, figure out priorities & overlaps, and then temporarily lock out those events, all while it's also processing those people who've gotten their carts done.  The wait can be an hour or more.  I think last year, my buddy's list didn't get processed until after 1pm.

Once you hit submit, you'll get a number as to your place in line.  This will update sometimes, or you can refresh the page to see it (hopefully) go down.  Once you get to the top of the queue, the events from your wish list will appear in your cart.  These will be events that still have enough tickets to satisfy your requests, and you will only get your top priority event at each time.  IIRC, you then have 10 minutes to finalize & submit your cart.  You will then have registered for those events.  If you don't submit your cart in time, the tickets that were temporarily locked to you go back into the pool.

So, basically plan to spend at least a few hours sitting by the computer waiting for your list to process.  IMO, don't do this from a tablet, and if possible, do it from a wired machine.  The last thing you want is a wi-fi glitch at the time your trying to get your car sorted out.

I think you get more than 10 minutes. The GenCon event page says 2 hours... I think.

G

2 hours?  That's generous, I always thought it was 10 minutes.  

I'm reasonably sure it's 2 hours, or at the least much more than ten minutes.