We always call FW front desk about four days prior to arriving. We faxed once, and they never saw it.
We even got to talk directly to 'site assignment' once, not sure how that happened. Any earlier than four days, and they won't have gotten your ressie from CRO yet ... at least thats what we were told.
Sometimes even that doesn't help, you get to go thru the book as you are standing there because no site has been assigned to you.
John
Northern IL
Polk City, FL (Mt Olive Shores North)