I've been stalking this thread for a while and think DBTY will be the next Tiffany collection item I want to buy, but that will have to be a few months time at the very least, since I caved yesterday and bought two items a few months ahead of schedule

(justification: in case of Jan 2013 price rise and lack of stock, as is currently the case on the website).
Was browsing on the UK Tiffany website and from the sounds of it, they only sell based on carat size? Or is that just the website? I would have asked at the counter yesterday except it was scarily busy.
If Tiffany only sells based on size, what are the diamond specs? (ie. I1-I3 grade?).