I agree with your strategy HB! I used to book exit row up front (a relative term here in WT!) upon booking and then just make sure I didn't print the boarding pass at T-24 so that I could see if the flight was going to have a good number of seats unallocated at the back just before heading off to the airport around T-5 or so...if there was a good block free i would then move to the back middle and hope for the best. It did work some of the time but the drawbacks are that very large groups of school kids and such would then sometimes be sitting around you as I believe very large groups can't do OLCI...also the definite drawback is that you eat last, get off last and are truly last to get to immigration control! (although your bags are usually there by the time you get to any belts if no-one has taken them by mistake).

On BA flights I personally find it better to try to get as far forward as possible but especially on TATL US carriers I would give this a go as my impression is that they are less full and the chances are better to get a row to yourself...but its been a few years since I flew any of them.

BotB