I personally have never stayed up to call right at 331 days since I think that is somewhat over-rated especially with the airlines putting in more and more sophisticated inventory managemnt - they often release seats later on as late as a few days before the flight itself.

We bought upgradable Delta fares RT to Paris in Jan for the trip in July (at the time no seats had been sold either way) and the last seat didn't clear the upgrade until June - and we're both top-tier Delta Platinums. I felt pretty comfortable with them clearing since I was watching the seatmap closely. Of course this is somewhat gambling - last November we ended up in coach for Atlanta to Tokyo since we didn't clear the upgrades even though we bought the ticket in Sept.

I'm about to buy another upgradable to Tokyo since my cousin getting married in Dec messed up my Singapore First award tickets.