How does waitlisting in general work on Regent.

I have a H cabin assigned (669)but decided to go ahead and waitlist for a F or G. At this point the entire ship is waitlisted for the December 1, Voyager Sailing.

How do they work it? Do people already on the ship have a higher priority then people not yet on the ship? or does it just go by when you get on the list.

I've been told the waitlist for H, F, & G are not long... don't know what that means.

Final payment is do September 3rd or so, and of course we are already in a penalty phase. What has been your experience? Do I have a decent chance of clearing the waitlist?