POJ,
My details are in the RFE tracker in case someone is interested.
Yes there used to be long waits in Miami , I have stood in line for nearly 10 hours for my interim EAD 2 years back , but there is total 180 degree turn now , you can set up your appt thru the web and that makes it very easy .
FOR GC STAMPING - you don't need to set up appt , it is a walk in, though initially i met a person who would not allow us ( my wife and i ) in , but then i talked to this other gentelman who understood what i was trying to say and let us in , inside we had to wait about and 1 hour and 15 minutes and about 10 -15 minutes for the stamping , it is very well organized .
This is my 2 cents
The documents they requested were
1) The approval letter ( ofcourse )
2 ) Passport with atleast six months validity left.
3) 1-94
4) The EAD card.
5) Two adit style snaps with your a number at the back
The number has to written with a pencil.