i think i am an expert at this. i use miles to upgrade myself and my family all the time.
my family and i have cleared many, many times before the EUA's have run.
CO's official rule was that the waitlist was eliminated 24 hour prior to dept.
on our last trip my little bro's flights had not cleared. he has no status.
he was cleared at check-in leading me to believe that the list no longer is eliminated at the 24 hour mark.
old school CO employees are not always up to current policies. I had a PC agent tell me that she has worked for CO for 20 years and that milage waitlisters were not allowed to be cleared at the airport.
bottom line, if you do not clear prior to 24 hours (i usually do), no other elite should have cleared either.
when you get the to airport, let an agent know that you were waitlisted for a milage upgrade and ensure you are first on the list. you should be before any elite. as said above, i have heard this referred to as P1.